Ice to Meet You 2022

Hey everyone!

‘Ice to meet you’ to everyone who does not know me already. This is my first time writing for the Ideaal!, so I sincerely hope you are as excited as me. To me, writing for the Ideaal! is hopefully a way to get to know the association and its members (even) better.

To all the new students: how did you like the first module? It might be hard adjusting to the university and everything around it, but activities from Abacus and student life, in general, are probably good support. I saw that they put Analysis 1 and Linear Structures 1 into the first module now, so I hope you all survived. But that is all behind you, so now fully enjoy the rest of this year.

This edition will definitely bring you some joy, which is much needed at this time of the year. Because, as you might have noticed, the world has gone dark and cold. My fingers are currently freezing off and the thought alone of turning on the radiator cost me a euro. Let this Ideaal! distract you from that fact and bring you some warmth in these dark times.

This edition we have a lovely set of articles, including an interview with the board, another

interview with the open day's team, and an exciting review of the film Smile. So grab a blanket and some hot chocolate milk, and enjoy this cheerful Ideaal!

Kind regards,

Xanti

Guest writers:

Chendo Helmink (External Thoughts)

Fulya Kula (Staff Says)

Luuk van der Werf (Dies 53)

Diana Dalenoord (Interview: Mariya Karlashchuk, From Student to Alumnus/a)

Ties Martens (Solving 3D-flow equations for blood vessels)

Matthias Schlottbom (About MaCS)

Jorn de Jong (Puzzle Solution: FrogFrogFrogFrog)

Raymon de Lange (Your Story)

Emile van der Veer (Fairness of Dice)

Marieke Snoeren (Review: House of Earth and Blood (Crescent City 1))

Ideaal! is the magazine issue of Wiskundig Studiegenootschap Abacus and the department of Applied Mathematics.

The responsibility for the articles published in this magazine lies with the original author(s).

The period of notice of Abacus is four weeks before the end of the association year (August 1st). That means that you must cancel your membership before July 4th. If you have forgotten to cancel your membership before that time, you will pay contribution for another college year.

Would you like to cancel your membership? Send an email to board@abacus.utwente.nl.

External Thoughts

Text: Chendo Helmink

The theme of this Ideaal! Is “Ice to meet you”. When I heard about this I immediately thought about how ironic it was that this piece would be in this Ideaal!. That is because at the moment I can not meet you readers physically and the only ice I see is the ice in my drinks. The reason therefore is that I am not in the Netherlands at the moment but in the beautiful SouthAfrica. As Officer External Affairs I have to travel to several places which suits me very much. I grew up in a family with parents who love to travel.

My parents have lived in several countries around the world like Cameroon and Guinea-Bissau. When my parents got married in 1997 it took only a few days before my mother was already leaving the Netherlands for quite some time. In the end my parents got work in the Solomon Islands where they have lived for 2 years till my grandmother got ill and they decided to give up their life there and get back to the Netherlands.

Another two years later my mother got pregnant and during the pregnancy my parents decided that they wanted to travel to Turkey since travelling with a baby would get a little more complicated. So in some way Turkey was the first country where I have been outside the Netherlands.

Since that time I have heard endless stories about all the amazing places where my parents have been. This caused that already on young age I got a lot of passion for travelling. The list of countries in Europe which I have visited is almost endless and almost every

year I can add at least one country. In 2013 my parents decided that it was time that I would also see how life in a different continent would be. We went for 4 weeks to SouthAfrica and this time has definitely changed my life. We have met a lot of different people over there but a few people I will never forget. One of them is a woman we met in a small village where we went. She would guide us around some places. After half an hour she was already asking if we were still able to continue. Turned out she was already completely exhausted so in the end we have guided her back instead of she guiding us. Back in that village a lot of children wanted to feel my skin. They did not really understand what I was because they had never seen a white person. Another group of people I will never forget are some people from an institution for the disabled. The moment we entered they started singing the national anthem and to see all those people gathered just to meet us was definitely one of the most emotional moments of my life. This was already almost the end of our journey through South-Africa so we decided to leave some chairs and a football over there. The joy I saw on their faces when they could have a football is indescribable. During this whole South-Africa trip I fell even more in love with travelling.

After this trip I went to several European countries. Some of these vacations I went partying with friends and some of them I went backpacking, for example through the mountains of Ireland and Austria.

I enjoyed these trips a lot but a few years later my parents came up with a really adventurous plan. They asked me to join them to go to Uganda to set up a kitchen garden for a whole village in the north of the country. The plan was

that I would live there for a couple of months and become a maths teacher in Kampala (the capital of Uganda) the rest of the year. In December 2017 we went to Uganda to make agreements for the kitchen garden and to see where we were going to live the upcoming year. We started at Kampala the first week and afterwards we went to the north. We decided to take a little off road because we were too stubborn to follow the exact route from Google Maps. This resulted in getting a flat tire in the middle of the wild. It was already quite late, but we decided to change the flat tire anyway, knowing there were likely lions quite close to us. In the end we managed to reach the north and we waited for the next day to look where the kitchen garden would be. When we woke up we were shocked to see that the kitchen garden would not be any bigger than a small garden as a lot of people have in the Netherlands. This was by far not big enough to feed a whole village. We unfortunately had to cancel our plans of living there for the next year.

Two years later Covid started and as you all know travelling was not really possible during this time. Now that we can finally travel again we decided to go back to the beautiful South-Africa. I hope you all got too know me a little better and especially about my passion for travelling. I hope it gave you some warm feeling in these Ice cold times. Once I will be back it would be nIce to meet you all in the Abacus room!

On the Couch...

Text: Jorg Gortemaker

Introduce yourself!

Em: Hello, I am Emile.

Ev: I’m Eva.

C: I’m Colin.

A: And I’m Anna.

How long have you been on the couch?

Ev: Like twenty minutes.

Em: Fifteen minutes.

A: Twenty minutes probably.

What is your favourite memory on this couch?

Ev: Studying for the ODE exam and just falling apart, it was great, lots of fun.

A: How was that fun? I did enjoy our study session, but how is falling apart fun?

Em: Preparing the Lego Masters activity, which happens on 11-012023, the date is not fixed yet.

C: It’s the first time I sit on this couch. I have no memories of this couch, if this area counts then the project that was a mess, that I had to do all by myself.

Who do you prefer to sit on the couch with most?

Ev: Marieke.

C: The people that are sitting next to me right now.

Em: Anna is always really helpful when I’m trying to study, and I don’t understand anything.

A: I like you guys too, Marieke as

well. I would like to see Jagi again. Also Eva.

If you could add an article to the Ideaal! what would it be about?

Em: I already added an article for this Ideaal!

Ev: I would go about a really long rant about how the frilly dress market is a good indicator of the overall economic prosperity of Europe.

A: I base my overall feeling of how well it’s going with the economy on how expensive one can of tomatoes is.

C: I have no idea.

Ev: What are you interested in Colin?

C: Nothing.

Ev: Colin has no personality.

C: Exactly, maybe I’ll do an article about personality, and how to get one.

Em: Just write down musical intermezzo and then put some sheet music on there.

What was or will be the highlight of your day?

Em: Going to bed and sleeping.

Ev: Buying 10 kilograms of rice.

Em: Oh yes, actually on this day yes.

A: I have training today and I think I’m gonna get myself poffertjes for dinner, so that’s pretty exciting. I’m also pretty excited about going to bed.

C: About going home and not ha-

ving to worry about anything maths related.

A: We’re doing great as you can tell.

Em: This interview is getting more and more depressing by the minute.

What would be the main course for your perfect Christmas Dinner?

Em: Curry with rice. Steaming hot curry.

Ev: Orange shrimp pasta that Lavinia had in Rome. Or ‘gourmetten’.

C: My parents always make boeuf bourguignon, which is really nice for Christmas. Usually they put red wine in it as well. That’s what I always look forward too.

A: Last year we made a filled pumpkin with pomegranate.

If you were able to solve any millennium prize problem, which one would you like it to be?

Em: Riemann Zeta.

Ev: I will go with Yang-Mills existence and mass gap. I don’t know what that is, it’s a quantum field problem.

A: I will go with P versus NP, because I think my housemate said that if you solve that the world has a big problem.

C: Navier-Stokes existences and smoothness. Only because we’re doing ODE and it seems related to it.

What game would you like to nominate as game of the year?

Em: I’m gonna say Draughts, because it’s fun.

Ev: I think it would be really funny if we all would really get into Go randomly. If the whole mathematics department would go: “You know what we should really learn, Go!”

I keep reading and watching Go manga and anime and I still have zero idea of how to play that game.

C: Halli Galli, just because I know a

Your Story

lot of people hate it.

A: Macchiavelli, I played it yesterday.

Charmander, Squirtle or Bulbasaur?

Em: Bulbasaur.

Ev: Bulbasaur.

A: Yeah.

C: I don’t know anything about this.

A: I also don’t know anything about Pokémon, but I do recognize Bulbasaur so I’ll pick that one.

Cauchy or Schwarz?

Ev: Cauchy because I like saying his name.

Em: We are on a couch, so Cauchy.

C: Cau”ggg”y.

What are you going to do next?

Ev, Em: Go home and buy rice.

A, C: Go to Numerical mathematics.

For the Harambee equivalent of the Ideaal!, I was tasked to collect statistics of a certain volleyball match, my goal was to alongside the usual ranking of the players who made the most points, mistakes, and an overview in a bar plot who did what how often, I also wanted to make a diagram (in the form of a digraph) which shows who play to whom. Based on a story of one of my current coaches also former teammate and to make my life a bit easier, I encoded the match such that a script I wrote in Python could make the appropriate figures with as less effort possible.

First, I am going to define how I encoded it in a bit more mathematically. For a match M let strM denote a string in the following from:

assume base 64 as not often the shirt number is above 20. If it is unclear which player performs this action, the player is denoted as #.

• Ak denotes what action is performed and is chosen from the following list:

• Hk denotes how well the action is performed and is chosen from the following list:

• Furthermore, I summarize the actions combined of the opposing team as ‘0##’ , '0#0' or '0#1' instead per player, as I am only interested in who plays towards to opposing team and if a point was scored by them.

“The player with shirt number 12 attacks the ball to the other side, a player of the opponents team touched the ball, but it bounces outside the field”

In this scenario I attribute the point to player with number 12 and write 'C51' instead of 'C5#0#1', had the opponent directed it inward to the field I would have denoted it as the latter. However, if the attacking player was from the opposing team (and player 12 would try to pass it) I would always write '0##C20'

Where for the kth action:

• Pk denotes the shirt number of the player performing the action, Pk is in a high enough base such that it is only a single digit. In the Python script I

From this one could see that I make the underlying assumption that an action is not bad if the ball is kept in play, which is in real life not always the case as someone can give a very bad pass, but the next player makes a good save that keeps it in play. Currently it is also based solely on manual input and is prone to human error, a real-life example would be at some point I kept inconsistently mixing up the numbers for lower hand and upper hand ball. Finally, to who is attributed the point is sometimes in a gray area. For instance, consider the following scenario:

I am not the first person who is writing this article and previously they just tallied everything on paper. At the moment encoding the match does not make it more efficient as it outputs the same kind of table as one would have by doing it by hand with the same speed, as I currently have Python not set up to also make the figures (and I won’t in the future because the figures Python creates are kinda ugly). The only benefit it has is it also preserves the chronology of actions, but that is something that is currently not needed.

Text: Tim Hut

Staff Says

Text: Fulya Kula

From a Semantic Theory to Teaching Statistics

Theories are vital to the scientific profession in bringing order to complex phenomena to comprehend, clarify, and anticipate. Inferentialism is one of the theories that attract attention in statistics education. The semantic theory, of inferentialism, formulated by Brandom (2000) locates inference at the core of human knowledge and fits well with the idea of statistical inference. In general terms, Brandom privileges inference over-representation. According to him, the ability to represent anything depends on human reasoning practices. According to the representationalist view, we can reason once we can represent. This view was criticized in learning statistical inference, to assume without foundation, that if students know the essential representations of statistics they can reason statistically (Bakker and Derry, 2011). As a consequence of the representationalist view, for instance, the statistics curricula have an atomistic approach, mean, median, mode, and standard deviation are studied singly. To overcome these pitfalls, Bakker and Derry (2011) introduced three points: (i) statistical concepts should be predominantly comprehended in infer-

ential terms, (ii) a holistic approach should be prioritized over an atomistic one (e.g., introducing mean and standard deviation together with the idea of distribution), and (iii) the illustration of an inferentialist approach in teaching statistics.

In statistics teaching, the idea that supports inferentialism is that statistics is not decontextualized wisdom but a discipline that imports statistical ideas and techniques in a conceptual context while connecting them to concrete conditions. In my opinion, inferentialism proposes a valuable theoretical lens that can brighten how students can learn to contextualize and integrate statistical and contextual considerations. A way to teach statistical inference, in line with inferentialism, is to teach statistical inference by starting with the population and picking up samples from this population (Kula and Kocer, 2020). We propose a new model to introduce statistical inference and name this as the direction of construction, as opposed to many sources in statistics that teach in the direction of application.

Inferentialism and representationalism can be better understood by the metaphor of using a microscope: doing statistics is like using a microscope to comprehend the anatomy of bacteria. One should be aware of the fact that the microscope magnifies the things it

is directed to and the relative size of the object is changed. The representationalist view, in this metaphor, would let students see the bacteria for the first time through a microscope without comprehending how the microscope works with rather a distorted idea of the exact size and anatomy of the bacteria. On the contrary, inferentialism would leastways let students be conscious of the fact that the microscope amplifies the object that it is directed to and the magnification process changes the relative size of the object concerning the rest of the reality.

References: Bakker, A. & Derry, J. (2011). Lessons from Inferentialism for Statistics Education. Mathematical Thinking and Learning. 13(1):5-26. 10 .1080/10986065.2011.538293. Brandom, R. (2000). Articulating reasons: An introduction to inferentialism. Cambridge, MA: Harvard University Press. Kula, F. & Koçer, R. G. (2020). Why is it difficult to understand statistical inference? Reflections on the opposing directions of construction and application of inference framework, Teaching Mathematics and its Applications: An International Journal of the IMA, 39(4), 248–265, https://doi.org/10.1093/ teamat/hrz014

Interview: The 55th Board

It has now been a few months since the change GMA. We sat down with the 55th Board of W.S.G. Abacus to check on them and see how they were faring and to ask them about what they have been planning for this year. Text: Lavinia Lanting

What was your favourite day so far?

C: Well, not the Candidate Board round.

N: The Constitution Drink was a lot of fun.

C: Yeah, that was a lot of fun.

J: It's really a tricky question.

R: I have not studied.

W: You didn't study for the test?

R: I did not study for the interview. What have we even done so far?

W: We played pool with Felix.

R: We did go pooling with Felix indeed.

W: I really liked yesterday too. I finally had a debit card.

C: The pub crawl was a lot of fun too.

R: Space Theme Drink!

C: I think it's a difficult question. Ooh, the interview with the Id… oh no, we were still a CB then. Today then!

N: A few days ago when the Ideaal! appeared here.

R: A few days ago when the Mini Almanac came out.

J: That was more of a surprise.

R: The Twin Drink was nice too.

C: The pub quiz from Formorrow was also lovely.

R: The Dies week was fun!

J: Especially since we won the Red Thread Game.

N: I really enjoyed our board year.

J: I am also really happy with our CB.

C: Yes, they are super cute!

What do you most look forward to?

N: The change GMA.

W: Already?

R: The Christmas dinner.

N: The CB announcement.

J: The CB round of our CB.

R: Even just having a CB.

C: I am also looking forward to being away from the boys for 3 weeks.

R: And where are you going?

C: To South Africa.

What will you remember most about your candidate board period?

C: Well, the Ideaal! interview.

N: When the Ideaal! came out while we were CB.

C: I honestly remember that the most.

W: That we were at camp preparing for the board presentation and we weren't stressed at all.

R: I wouldn't easily forget the CB round either.

J: It was a bit short though. I would have liked to visit a few more associations.

W: I thought it was fine.

R: Yeah, I thought it was fine too.

W: I had had enough salt for the day.

N: Yes, I agree. It was all nice and salty. Can't be good for you.

C: Can’t be bad either.

N: Well…some things were a bit unhealthy.

C: Uh, the coffee dates.

N: It was all kind of the same every time though.

C: I thought picking out suits was funny actually.

N: Yes, browsing through a thousand different shades of blue…

How did you decide on your board colour?

N: It was very simple.

J: ‘vorange.

N: We took a look at the colours that were up.

J: Orange was missing.

N: We could have done blue as well. It hasn't been used in a while.

C: Or purple.

R: Emerald was also an option.

C: Yes, since our number is 55 and 55 years of marriage make an emerald wedding.

R: Then we could be very annoying and tell everybody it wasn't green, but emerald.

N: If I had to choose, it would have been pink.

R: Fortunately, you didn't have to choose alone.

N: Yes, nobody agreed with me.

W: I already have pink clothes from the Twick anyway. Very beautiful by the way.

And how about your motto?

R: Hihi.

C: Thinking for a long time and searching for a long time.

N: It was very simple.

C: Oh!

N: No no, it was very difficult. We searched very well.

R: It had to be something that is proper and easy to shout and then we started looking through cartoon quotes. It all just didn't sound very good and then we suddenly came across this one and it stuck with us.

What has surprised you most in the last weeks?

J: The dishwasher.

N: Yes, that was a nasty surprise.

W: It's always the best thing about the whole week: washing those

mugs.

C: There are more small tasks than you thought beforehand.

N: Every time I think again: oh yes, I actually have to do this too.

C: I'm also surprised that we're still complete.

N: Chendo thought he would be long gone.

C: Yes, indeed.

R: Well, we had to wait a really long time for the debit card to arrive.

W: That's not surprising, but it's sad.

R: How easily you get distracted here.

J: It's kind of cute that you only found out this year.

W: Yes, it was already noticeable during our CB period last year.

Assume Abacus had an infinite amount of money. Which activity would you organize?

C: Swingo.

W: Swingo with live performers.

R: Yes! Swingo with a live band!

N: Yooooo! That's sick! That's really sick!

R: Abacus World Cup pool.

C: Abacus World Cup pool where

the winner wins tickets for the final. And I would build our own stadium.

N: Yes! F.C. Abacus' home stadium.

C: Just build over the Grolsch Veste. We use the Grolsch Veste as a miniature.

R: And what would you call it?

C: The Abacus stadium. No, the ASML Abacus stadium.

N: I would buy the Starbucks and remove it.

C: Then we can build a water park here with slides from the balcony. We can then fill it completely with beer so that you are swimming in beer.

J: And then organize a party here.

R: Not just any party. The EducaFest.

N: No, that's for the lustrum of Educafé. How old is Educafé?

C: A few years.

Describe the new freshmen in three words.

R: They're gone.

J: That's three words. C: Uh…

R: Chendo, behave yourself.

N: That's also three words. Nice description for the freshmen.

C: Should I take your feedback into account right now?

R: Nope. Be your own person.

C: I'm clamming up now. I give the word to Jorrit.

J: It doesn't work that way.

C: Then…still with many.

R: It's nice that we're trying to make some kind of sentence.

W: Proactive. At least, the freshmen in the FMC.

J: Won’t pass.

C: Future CB.

R: Future damn candis.

C: Have much fun.

R: Yes!

C: They're cute.

R: Are very friendly. I think this is almost like a game: find a sentence with three words.

C: We are board!

W: Ah yes, three words about the freshmen: we are board.

C: Let that be clear. I think they should be more aware of that.

N: Very nice, but…

R: Freshmen are friends, not food.

Why are you better than the previous board?

J: What kind of question is this? Niels Apeldoorn is standing right there.

C: Because 55 is 'vo and 54 is anti'vo.

N: 55 is a higher number and a higher number is always better, right?

C: Of course we are also better because we have a nicer Chairman, we have a nicer Secretary, we have a nicer Treasurer, we have a nicer Officer of Internal Affairs, we have a nicer Officer of Educational Affairs… and I knew this was going to happen…

R: And also a nicer Officer of External Affairs.

C: Woohooo!

W: I think it's mean for Margriet.

C: I don't. Nothing against our previous board, but we are just much more fun.

W: We now have a much better Thales contact person than the previous board.

C: And we have Little Chendo.

N: But it was given to us by the previous board.

R: No! It was given to us by Sinterklaas.

What is the role of Little Chendo within your board?

J: Mental support.

C: Mental health.

J: Otherwise I can't make minutes.

R: He is indeed Jorrit's minutes making buddy.

C: And my hug buddy.

R: And Niels’ pillow.

C: He's always happy. Even when he encounters difficulties, he always keeps smiling.

Were there moments yet where you asked yourselves what your predecessor would have done in your place?

C: Yes, enough.

N: Every day.

C: When companies come up with difficult questions.

R: I think you wonder about that in quite a lot of situations, especially when you're in doubt about something. Fortunately, it is easy and accessible to ask.

How is your experience with being a board member in comparison to being a committee member?

C: Tiresome.

R: Oh, very different.

N: We are much more responsible. You can get away with doing nothing within a committee.

J: No, that's a bad example.

C: As a board member you are obliged to participate in many more social activities.

R: As a board you do many more overarching tasks. You keep an eye on everything, while as a committee member you usually have a specific task or organize a specific event.

C: You have to have much more contact with other people extern to Abacus.

W: As a committee member, if you have any questions, just ask your board person.

C: And now you are the board person yourself.

Which new Abacus merch can we expect this year?

C: Underwear.

J: Read the Ideaal! from when we were CB.

W: Newer and nicer sweaters.

R: There may be a limited edition one-off jumper. What more? I look at our Officer of Merchandise Affairs.

J: What?

W: You were here when we decided that, weren't you?

Where will the Active Members Weekend be?

J: We know that, don't we?

R: Texel.

W: Wessel.

R: To Wessel with Wessel.

J: It will either be Texel with Wessel or Wessel with Wessel.

R: To Wessel via Texel?

W: We can also go to the Brakke Berg.

Who is your favourite mathematician?

C: Bernoulli.

W: Benford.

for Dutch national football team orange if I were you.

R: I'm not very familiar with colours.

W: Hamka's orange.

N: Orange Nassau. Wait, apparently there is a UT orange from the University of Tennessee, but my favourite orange is #ff5500.

W: Is that still orange?

N: Yes. Yesyesyesyes. Well. Yes. It's called Mystic Red though.

C: I'm not into mathematicians.

N: The guy who invented L'Hôpitals rule.

C: Isn't that L'Hôpitals himself?

J: No, he bought it.

R: Felix Schwenninger. Oh, you have Euler too. He exists. He was smart.

J: I'm so uninspired: Ramanujan.

Which is your favourite committee to follow until now?

N: I say the LIMO committee.

R: This committee has not started yet, but I am very much looking forward to guiding the Cantus committee.

C: I am very much looking forward to guiding the Twick-In 2023.

W: The Auditing Committee is always fun and useful and there is always good food, but I think the FMC is more fun to follow.

J: 'Vo for the Ideaal!

If you were a specific shade of orange, which one would you be?

J: There is only one orange.

C: I'm going for oranje boven. R: Mandarin. No, sunrise. It certainly must exist.

C: Sunrise is an emotion. I would go

How do you feel about the Netherlands taking part in the World Championship?

C: Oranje boven. Viva Hollandia

R: Let's not make any political statements here.

J: I think it's remarkable that they qualified.

W: I can agree with that.

Chendo: were you aware of the fact that the Football World Championship took place in South Africa 12 years ago? Now that you know that, what are you going to do in South Africa?

N: Take revenge.

C: I'm going to see if I can find some Spaniards there and then I'm going to… no, I don't really want to meet any Spaniards at all actually.

J: That you can go there without getting PTSD is a wonder to me.

C: Well, but I've already been to South Africa three years after the World Cup.

R: I can't remember the last time there was so much hype for the European Championship and the World Cup.

C: I'm going to have the World Cup take place there again. I'm going

there for a consultation.

We have noticed that the inhabitants of a certain house have slowly started taking over Abacus. Wessel and Niels, how will you prevent this impending colonisation?

N: By also living there. Wessel is already well on his way.

J: He slept over last night.

C: Now he has to sleep over again on December 19th.

W: December 19th?

C: Yes, because then the Ideaal! comes out.

W: I should actually move further away.

N: Maybe we can dig up the house and move it to Oldenzaal.

Niels, as the only 3rd year in the board, how will you ensure that more 2nd years will apply for the next board?

N: Cry. Maybe pray a little.

W: You can also ask them yourself. N: I actually think it will turn out just fine. I think that no people from my year will sign up, so it will have to be 2nd years.

Niels, as Officer Educational Affairs, how many extra resists can people expect to get this year thanks to you?

N: -1 extra resit, just like I said during the CB interview. Everything is fixed, so it is not necessary. Everyone passes.

C: It has gone wrong so far.

N: Maybe we should have included it in our policy. Then again, freshmen don't count, so it's correct again.

Jorrit, who of the entire board has the most useful things

to say during the board meetings?

J: Are useful things being said during board meetings?

C: Well, go ahead and have a meeting on your own next Monday. You won't see me there.

W: Why are you still making minutes if nothing useful is being said?

Jorrit, as board representative of the Ideaal!, how will you ensure that the popularity of this amazing magazine surges among the Abacus members and the staff members of Applied Mathematics?

J: We can send a promotional message for it: the Ideaal! is here!

W: We can take them with us on coffee rounds.

J: That's nice too.

Wessel, how are you going to protect the money this year?

W: Look, the past few weeks it's been really easy. There was no debit card, so no one could spend money.

N: Smart.

R: Clever tactic.

W: Now we have a debit card, so now it gets a bit more difficult.

N: Everything is less secure all of a sudden.

C: Have you checked whether it was still laying where it should be?

W: I don't know. If all is well, it is still there, in the middle of the board table.

J: Oh, then it's safe.

C: We just have to not include that in the Ideaal!

N: It's always under your keyboard, isn't it?

W: Yes. That's my secret spot.

R: Don't look!

Wessel, we noticed the Rabobank sent you a second debit card that looks suspiciously similar to your own. How will you know which one to use?

N: Well, the one with less on it…

C: That’s the one from Abacus.

W: I have already received many suggestions for this, such as completely covering the card in stickers or marking it with a marker.

Chendo, who do you like sneaking money from the most?

C: ASML because they pay the most.

W: What might they do next?

C: They were going to shoot a film with a coffee machine explaining how to make coffee and maybe there was to be some advertising in it too. Oh, and I often try to contact Thales, but that goes a lot less smoothly.

W: They just don't pay at all.

Rutger, what is it like to lead this board so far?

R: Yes, nice. Keeps you busy.

N: Always a lot to do.

R: It’s nice work though. N: No dull moments.

R: And a little laughter.

C: Sure?

R: Yes, I think so.

Rutger, how many times have you had to impose censorship on words spoken aloud by fellow members of the board?

C: More often than not.

R: That has come up a number of times already. But they have got better. They do learn. It is becoming less and less common.

C: No, we just say that kind of stuff when you're not there.

N: We've got smarter.

R: I hadn't taken that into account yet.

Will you have official board pictures by the time this interview is published?

R: Yes.

N: Yesyesyesyesyes.

C: Yes, absolutely.

W: 100%.

R: I'm going to tell the guy later that

Dies 53

Text: Luuk van der Werf

Two years after your board year at Abacus it is time to honour your board number in the best way possible: organising the ‘vo-th dies.

This year it was time for board 53, and we joined the committee with everyone (except Clara). Also, since it is a good tradition we had freshmen Jiska joining us. With the six of us we were determined to organise an unforgettable week of festivities.

After a fun brainstorm we came up with the theme: Around the world in 5.3 days, of course a hint to Jules Verne. First we came up with 53 days, but soon we found out that the week starting on Monday and ending at the party on Friday night till Saturday morning would be exactly 5.3 days. This would mean that the party would have to go on until 7:12 Saturday morning: ‘easy’.

We opened the dies week on Monday with a lovely international lunch. Multiple people prepared food from different cultures, with as star of the show a lovely Dutch frikandellen pie. On Monday the red thread game also

we can go on that day. No, that is not true. I'm still waiting for confirmation from Felix.

Do you have any last words?

C: Well, one more according to me.

W: Yes, a few more.

Everyone: ‘We hebben een woonboot, het ligt aan de Amstel. We hebben een schuitje, ‘t is ons Ideaal!. Ideaal! ‘vo!’.

started. Teams started solving the puzzles with insane speed, and we also got some beautiful pictures and movies.

During the week the teams gathered parts of a world map by solving the daily puzzles.

On Wednesday we had a lovely Asian-ish dinner, and afterwards you could craft your own transportation method, or just enjoy a cold beverage.

On Friday teams could complete their world map to find the final solution of the red thread game. The team of Wout, Justus, Hugo and

Cathy was very quick and solved it the fastest. Congratulations! At 16:00 it was of course time for the weekly FriAD, and this week it was themed specially for the Dies week. During the FriAD, the winners of the creativity prize were announced: congrats to team 52!

After a very nice drink we all went to the Vestingbar. We had a lovely night, and sung our hearts out at 00:00: the 19th of November!

Review: Smile

Text: Lavinia Lanting

If you know something about horror films, you might be acquainted with the idea of almost each and every single recent horror films having a chills inducing trailer that makes you wonder if you could actually make it through the entire thing, while the film itself is often laughable at best. As a side note, more films have amazing trailers only to be laughable themselves: it suffices to think of for example ‘Morbius’, produced by Sony, the trailer of which promised wonder, while the film quickly became a joke to communally cackle at. Regardless, while that has usually always been the case as of recent, ‘Smile’, directed by Parker Finn and released in the Netherlands on September 29, 2022, was sort of an outlier in its genre: its trailer truly was one of the funnier ones. Of course this meant, in my eyes (so the eyes of a horror lover, who even watches bad horror films just because they are genuinely funny at times) that I HAD to go watch ‘Smile’: how could I pass up the opportunity to watch what could have been a gen of true comedy on the big screen? Exactly, I couldn’t, so I picked a date to go and, as of-

ten happens, dragged Jorg along to share a few laughs and have a nice date night together.

Well, it turns out I was very wrong about this film. As a matter of fact, ‘Smile’ is quite a good film and this is due to a multitude of facts: the characters (especially the main character) make generally smart choices (as opposed to what typical horror film characters do), the pace of the film enhances the story and the jump scares are neither cheap nor predictable. This was quite a pleasant surprise, seeing as the trailer made the main evil of the film look like a funny gimmick and actually spoils quite a bit of the film. In spite of this, the film is very much worth watching and has much to offer in terms of experience (provided you actually enjoy the horror genre to some extent).

‘Smile’ is the story of Dr. Rose Cotter as, following an incident with a patient, she finds herself confronted with a supernatural being only she can see and which always shows up as someone she knows having a creepy smile plastered on their face. While this may sound silly, don’t let yourself be fooled: the simplicity of the concept is exactly what works so well about ‘Smile’ as time is placed into conveying the dread experienced by the main character rather than into having a very cool creature that is not scary at all. The story spans over 5-6 days during which Rose tries to find a solution to the impending doom hovering over her head. You follow her through dread and research, scary moments and decisions on how to fight back and it is exactly this slow pace that works so well: you know danger is there every single day you follow her, but you don’t know where or when it will make its move nor do you know how. Rose, on her part, does carry the film to some extent and the fact that she is a scientist makes her an appealing character

who makes smart decisions. This solves one of the most common issues in horror films too: protagonists you cannot relate to, because they make decisions which are obviously detrimental to both them and their loved ones and because they make decisions that any smart person would NEVER make in their same situation. To further bring my point home, I will give you an example I often use of bad to the point of funny horror film: 'The Midnight Man'. This film is based on a Creepypasta which contains the recipe and rules to summon the Midnight Man and play a game of hide and seek with him. The two protagonists find an old board game and decide to play it. Of course, instead of reading the rules and then playing, they play as they go and initiate the game only to realise that part of the rules of the game have been taken out. By this I mean that the rules are written on a piece of paper that has clearly been ripped apart through part of the text, yet they don't realise this until they get to that point with reading, which is absolutely stupid. In addition, a friend of theirs comes along halfway through the film, proclaims herself an expert on Creepypastas and then proceeds to explain that she can only help by participating in the game. Anybody who has read at least one Creepypasta knows this is foolish at best and deadly at worst and, indeed, (SPOILER ALERT) she dies first. What a surprise. Unlike these characters, Rose goes about battling this evil in a very methodic and thought through way. She looks for only the necessary help and researches the issue thoroughly, which is at least believable and creates immersion into the film for the viewers.

So, while horror is not necessarily a genre for everyone, if you do like this kind of films, you should definitely consider watching this one. Who knows…it might just put a smile on your lips.

Interview: Mariya Karlashchuk

Text: Diana Dalenoord

Mariya’s experience

Studying Applied Mathematics is not always easy, but it is incredibly fascinating!

After secondary school, I still didn't know exactly what I wanted; I was in doubt between languages and mathematics. After a student for a day in Applied Mathematics at UT, I knew it: 'I'm going to study Applied Mathematics!' Studying at a university was a totally new experience. Of course, the way of absorbing knowledge is a world of difference, but also the fact that while I was one of the best in my class at secondary school, I was now an 'ordinary' student. I was somewhat insecure and found the first two years of the Bachelors quite tough. I was supported in this by the Bachelor coordinator Brigit Geveling and the study advisor Lilian Spijker. Partly because of their advice, I am now an MSc Applied Mathematics graduate.

So, although I found it quite tough, I enjoyed everything UT and AM offered me. I enjoyed the differences between secondary school and UT and the people I was exposed to. I soon learned to stand on my own two feet and changed into the person in who I am today. Unlike VWO, here at UT, I was able to get everything out of myself, and I liked that.

Minor ‘Leren Lesgeven’

In the third year, it was time to choose a minor which was not necessarily related to Applied Mathematics. I chose the minor ‘Leren Lesgeven’ and found myself in a completely different world, doing an internship at a secondary school. Although I found it an exhausting

minor because you have to deal with classroom management, I found it very interesting. I liked the younger classes the most, I got to bond especially with the first graders and also taught a third-grade class with adolescent youngsters, which was really tough. Due to an additional year in my master’s programme and the preference for younger classes, I did not choose the master’s in Science Education & Communication later on, which is focused on the older classes at secondary school. It was a cool time, I learned to give myself to the students, to be focused in class, to teach the youngsters mathematics and keeping them in check. It was quite a task, but it was extremely rewarding.

Looking for exoplanets

After the minor, I started my Bachelor’s thesis which involved finding exoplanets. These are planets orbiting a star other than the sun. They were first discovered in the 1990s and more and more exoplanets have been discovered since then. It is difficult to find these exoplanets because they are very weak light sources, do not emit light themselves and are often irradiated by stars. The task appeared to be quite challenging, but its statistical background made me very curious. And so I started the assignment under the guidance of Katharina Proksch (EEMCS-MOR). The thesis involved statistical hypothesis testing, for which I needed to dive deeper in the statistical and probability theory and state everything correctly and clearly as in a practical experiment. After testing my hypotheses on a statistical model, I could eventually locate exoplanets in my data!"

Even more mathematics

Because I still hadn't had enough

of mathematics, I decided to do the Master's in Applied Mathematics as well. I chose the (then) new specialisation 'Mathematics of Data Science'. I discovered new developments within statistics, which had always interested me, mainly in machine and deep learning. I really felt at home here because I was always fascinated by the analysis of big datasets and the application of mathematical models on them, such as weather analyses and finding shortest routes on Google Maps.

After following many interesting courses in the data science track I could finally put all my energy and enthusiasm in my internship.at TNO. I worked on predicting tracks of objects that can be detected by radars. Such an object could be an unknown aircraft flying in a specific orbit. Using machine learning, you can figure out how fast it is flying, where it is flying to and what movements the plane is making. By combining all this data, I could predict what the path would be of an approaching drone. These kinds of predictions are carried out by the Defence, Safety & Security Department.

From black and white to full colour

During my graduation project, I worked on a method of how to look at CT data created by scans. For example, you can look at the different parts of the heart and whether everything is in the right place as you would expect. Currently, specialists use black-and-white reconstructions, and they indicate what is where, this causes a loss of information which you want to avoid. You want to see all the specific things to determine if there are any abnormalities, so you want to be able to look for any diseases quickly. We can improve this method

through deep learning, which takes you from the data straight to the detection of illnesses, without having to make a reconstruction first. The sinusoidal waves indicate the intensity of X-rays (which pass through the patient) that allows us to determine what we are looking at exactly. For example, lighter colors indicate bones, where darker parts indicate lungs. You can reconstruct these waves in a regular CT image, where you can locate parts of the heart, this is called segmentation. My method skips the reconstruction and goes straight to segmentation, which I indicate with a certain color. This way, you lose less information. If the specialist still needs more background information, he can always request the reconstruction. I found this enormously fascinating because I was working on a medical application that has an im-

pact on society and can make the world a little better.

Defending my graduation research

And then it was already time to graduate. I was quite nervous beforehand. But fortunately, my parents, brother and boyfriend - as a safe beacon - were present, which provided peace of mind. Everything was ready in the room, people trickled in and before I knew it, the room was full of interested people. At the first slide, I had to get into it, but then it went like clockwork and felt like an expert was speaking, unreal really. After my presentation, I was quizzed on some pretty difficult questions, but fortunately, I was able to answer everything satisfactorily. Graduating is really a special experience, it feels like being in a movie, but after signing

your diploma you know for sure: This was REAL!

New Challenge

After enjoying lots of free time after my graduation, it was time so start thinking about what I wanted to do now. Applications to companies were sent and after some referrals via my friends I have found a job!

In December I will start working at Agentschap Telecom as Data Scientist, which will definitely be a new exciting challenge to look forward to!

Bachelor’s: Applied Mathematics @ UT, NL

Master’s: Applied Mathematics @ UT, NL

Name: Mariya Karlashchuk

Solving 3D-flow equations for blood vessels

Text: Ties Martens

Inside blood vessels, plaques can form on the vessel walls leading to a narrowed passage for the blood to flow through. As the plaques grow bigger, the risk that the blood vessel will be clogged becomes larger. As you can imagine, whenever this happens inside blood vessel that supplies the brain with blood this can have serious consequences. This problem is called ‘carotid artery disease’ and it is one of the most common causes of stroke. Luckily, when this problem is detected there are ways to reduce the plaques’ size and to increase the blood flow through specific arteries. However, these are usually drastic surgeries that could have an impact on the patient’s health, so it would be nice if it was possible to detect whether a certain person is at risk or not.

Quantities of the blood flow like blood velocity, blood pressure and wall shear stress were found to correlate with plaque development inside an artery and are thus useful predictors to use when deciding whether surgery is recommended for a patient. Quantities describing this blood flow can be determined

using methods like inserting a catheter into the blood vessel. However, of course invasive methods like these often have its complications and risks, and are often limited in accuracy because of real world influences.

Therefore, if non-invasive methods could have the same level of accuracy (or better), these would be preferred.

A possible approach would be to use MRI-scans of the blood vessels to find the shape of them, and modelling the blood flow inside these arteries by solving 3D-flow equations inside them using patient-specific estimates for the values of the boundary conditions. This is exactly what I have done in my Bachelor’s Assignment.

Constructing an artery model

The medical data obtained from MRI scans are in the form of a stack of pictures, where each picture shows a slice of the artery at a different height. To extract the position of the arterial walls from these pictures is a complicated task as the images are often of poor quality and because of branches in the artery. Luckily, Dieuwertje Alblas

from the Mathematics of Imaging and AI department had already made a segmentation algorithm for this such that the starting point for my project was a dataset that contained slices of 32 points each, that describe the arterial walls of real patients.

The challenge now is to construct a 3D mesh that gives a better description of what the artery actually looks like based on these datasets of points. Of course, this can be done in a variety of ways which each have their advantages and disadvantages, and for my project I took a very basic approach in which all of these points inside a slice were connected with their two neighbours such that you get a set of rings. Two adjacent rings were then connected by pairing the two closest points inside these rings and forming a zigzag pattern. After the rings are all ‘sewn’ together like this, the created mesh is closed on both ends by interconnecting the points in the first and the last ring. Then, some heuristically found smoothing algorithms are applied that perform topological operations on the mesh to get to a more regular spaced and refined model. Finally, the interior of this mesh is being filled by genera-

ting tetrahedra’s inside the mesh.

Solving flow equations

The blood flow inside the artery can be described by its velocity (vector) and the pressure (scalar) at every point of the mesh. To find values for these we can solve the NavierStokes equations. These are a set of elaborate partial differential equations and no analytic general solution to these have been found. Therefore, a numerical approach is

Chain Interview

Text: Eva van Laar

Hello, Ideaal! readers. Let's see what your fellow Abacus members think about these random topics in this edition's chain interview!

What is your favourite music to listen to while studying?

Xanti: I mostly listen to focussed jazz and techno. In the past, I also listened to Mark Rober’s playlist.

Where is your favourite place to visit in Enschede?

Emile: The Educafe because I am there most of the time and the people are nice.

How many toddlers could you beat in a brawl?

Jasper de Jong: 1000 toddlers, I think that is the amount where they will eventually tire me out.

How many maths students are needed to beat Rico Verhoeven?

Emma: 60 maths students, more than 50 seemed good.

What is the most embarrassing thing about your Spotify wrapped?

Lars: Surface pressure from Encanto is on my top 5 songs (I think it’s a good song).

If you were a Pokémon what would your type be?

Mei: Physic - because I like Psyduck

needed, where boundary and initial conditions can be found either from medical data of the patient or by using a generic value from literature. In my project I used the latter one and solved the Navier-Stokes equations using numerical solver software.

Results

All of these steps were performed on an example dataset and the results for this were visualized to

give a nice indicative view of the blood velocity and pressure profile inside the artery. This method is promising as it gives qualitatively good solutions, but even though a lot of simplifications were made for this model, it still takes quite some computational time to calculate solutions. To speed up these computations, graph convolutional neural networks are an interesting future alternative to cut down on computation time and improve accuracy.

and Mewtwo.

What is your favourite anime or Film?

Sam Hallett.: Inglorious bastards because Tarantino is a good director.

Who is your favourite teacher at the uni?

Luuk: Clara Stegehuis ’vo (but also actually a good teacher).

What is your most listened-to song on Spotify wrapped?

Olaf: Are you mine - Arctic Monkeys.

What do you think about when someone says Olaf (only the snowman)?

Sam Baak: Definitely the snowman?

Are you excited about Christmas?

Chendo: Yes, because I will be in South Africa and the Christmas puzzle is then.

Are you excited for the Christmas puzzle?

Hugo: Yes of course! Everyone should be excited!

What is your favourite Christmas dish?

Wessel Heerink: Fondue

How many poems have you written for Sinterklaas?

Rutger: At the moment one and a half, the best poems come last minute, I have Sinterklaas tonight.

What is your favourite item/snack in the abacus room?

Wout: The blue M&Ms because they are delicious and crispy.

What is your favourite name to scream?

Martijn: MOUNTAIN

If you could change one thing in Abacus what would it be?

Arnout: We should add beer in the fridge

Would you rather have unlimited bacon but no games or games, unlimited games, but no games?

Marleen: I can’t eat bacon so the second option

If you could have an unlimited amount of stuffed animals of one animal what animal would it be?

Florian: Koala

Who is the most trustworthy first year?

Mark: First years are not reliable.

About MaCS: Mathematics of Computational Science

Text: Matthias Schlottbom

MaCS is the abbreviation of ‘Mathematics of Computational Science’, and we are working on various mathematical aspects of numerical methods. These range from the development of fast numerical solvers for very large systems of equations over error analysis of numerical methods to the solution of inverse problems. We apply our methods in many fields from physics and engineering, e.g., in the design of metamaterials, biomedical imaging, or subsurface imaging. If you are interested in that, let me invite you to discuss with us possible internships or final projects.

To get a better idea, here is a brief overview of our group:

• Tugce Akkaya: The research question that her PhD work seeked to answer is "What is the damping properties of rainwind induced oscillations of inclined cables?" at the Mathematical Physics department. One of her courses is ‘Introduction to PDEs’ (B-AM). She is currently appointed as Teaching & Learning Fellow for our faculty.

• Fleurianne Bertrand: Her work is strongly motivated by challenges related to the modeling and the numerical simulation of physical phenomena and it contributes to the development of numerical schemes for the simulation of problems in continuum mechanics. A significant

part of her research is devoted to the investigation of structure preserving finite element methods. In this framework she also studies abstract properties of finite element spaces. In the master, you’ll meet her in the courses Scientific Computing and Finite Element Methods.

• Philip Lederer: You may not have encountered him yet, because he is going to join us in March 2023. His main interest lies in the numerical analysis of partial differential equations (PDEs) describing the motion of fluids. Next to his research on incompressible flows, such as the motion of water, he recently started to investigate also acoustic phenomena in compressible flows. For this, he develops new finite element methods and algorithms to approximate the solutions.

• Carlos Pérez Arancibia: You can probably recognize this long name already, if you have taken Analysis I and II (B-AM) during this academic year. Carlos' research interests lie at the intersection of wave phenomena, boundary integral equations, and high-order PDE solvers, with applications in layered and periodic media scattering, waveguides, and inverse design of optical metamaterials, among others.

• Jaap van der Vegt: His main interest is in the development, theoretical analysis, and application of finite element methods for PDEs with applicati-

Puzzle Solution: FrogFrogFrogFrog

Text: Jorn de Jong

I could explain the solution myself, however people on the internet can of course do it much better.

The basic idea is to consider this problem as a graph problem. For the full details, see OEIS A347301 (https://oeis.org/A347301).

ons in physics such as wave problems in electromagnetics, fluids, and solids. Although his formal retirement is approaching, he will stay active in mathematics and continue to contribute to the research of our group and at USTC in China.

• Matthias Schlottbom: My research is in the context of analysis and numerical analysis for (high-dimensional) PDEs, with applications, e.g., in optics or medical imaging. To solve these PDEs numerically, I do research into accurate low-order models as well as finite elements. Having fast, accurate and robust numerical methods at hand, I am also interested in data assimilation and the solution of inverse problems, such as optical tomography. You may meet me in the Numerical Mathematics class (B-AM), or the master classes PDEs or Numerical Methods for PDEs.

As you have noticed, the words ‘analysis’ and ‘applications’ appear frequently, and it is true that our work is often carried out in collaboration with others, for instance, with colleagues from the Applied Mathematics Department, other faculties, or even other universities.

I hope this short article gives you a first impression of MaCS and the topics we are working on. If you do want to know more, do not hesitate to knock my door or to send me an e-mail.

Text: Raymon de Lange

My new Hobby

Five and a half years ago, as of me writing this, I went to my very first pop culture convention. I went there together with a good friend of mine, with both of us having effectively no idea what we really expected to find there. The convention at that time was AnimeCon, a convention specifically centered around Japanese pop culture, something me and my friend were both very interested in at the time. Although we had little idea of what to expect, we were heading there mostly hoping to meet some fun new people sharing our interests and maybe learning a new thing or two about something we enjoyed engaging with. Something I certainly did not expect to find there, was a jaw-dropping amount of people walking around in fantastical costumes, each one more meticulously pieced together than the last.

Those people had gone to the convention hall in Cosplay, short for “costume play”, dressing up as characters from some of their favourite franchises, TV shows, or videogames. I still remember being awestruck at that time by seeing near-perfect imitations of characters I had been a fan of for many years casually roaming the convention hall, and even more so by the scale and quality of all the costumes, which went far beyond anything I had expected possible. The entire convention experience had given me far more than I was expecting to get out of it, and needless to say I went to the convention again the next year… and the year after that.

Naturally, these conventions were no exception to the great number of events that had to be delayed or outright cancelled due to the Covid-19 Pandemic, and it was not until June of this year that I was finally able to go to a convention again.

Whilst my interest in Japanese pop culture had declined somewhat over the past five years, I could not help but still look forward with great excitement to the convention experience as a whole, especially since the intermission by Covid had come with a fortunate silver lining.

Some of the newer faces at Abacus might not know, but before the pandemic, I used to have significantly shorter hair, and I had been growing it out during the intermission. It was then to a most welcome surprise that during this time one of my all-time favourite shows had got a new season, one that introduced a character with hair very similar in colour and length to mine. Not long after, I had decided for myself that this character would be my first serious attempt at a cosplay of my own, and I would no longer be simply a spectator at the conventions.

With a lot of help from others, I was able to bring this character to life, and pay homage to a show I had been a fan of since I was 13 years old. This itself was a great experience on its own, and at the time I mostly intended for the cos-

play to be a one-time thing. However, this changed drastically after I had walked the convention floors in my cosplay, where I was greeted by person after person who recognized my costume and wanted to take a picture with me. Seeing that many other people as excited as I was to see this character brought to life, and bonding with them over it was an experience that I will always cherish dearly.

Since then I have found other conventions which also attract cosplayers, and what started out as a casual side-event throughout my years has now grown into something that might very well be a long term hobby of mine. I will soon start working on my second cosplay, and while I am still very much an amateur, I simply cannot wait to see the end result and share it with others.

Thank you very much for reading, I hope I was able to share some of the joys of my experiences with you through this story.

Kind regards, Raymon de Lange

A Day With... The Open Days Team

We had the pleasure to spend some time with the members of the Bachelor Applied Mathematics Open Days team. They walked us through their tasks and what goes into organising succesful Open Days at the University of Twente

Could you introduce yourselves?

A: I’m Anouk, I’m a 5th year Applied Mathematics student, but you probably all know that. We don’t really have roles within the Open Days Team I think, we're just in the team. Maybe only Niels (Apeldoorn, red.) has a special role, because he is a double student, so he is extra wanted.

Em: And Jorrit is also special, since he is the only one of us with a German language-tag.

A: I’m just old, so I have experience with the Open Days...

L: Well, you are also the workshop expert

Ev: I’m Eva, and I’m also the host of the online Open Days.

J: And Emile is the freshman of us.

L: I’m Lavinia, I’ve the Italian tag, I’m also doing way too much for the Open Days. I’m the team captain for AM, at least till this year. I’m also the faculty student coordinator, which sort of means that I suffer.

A: Because you get all the logistical complaints.

L: And I am the one who has contact with the central Open Days team.

With how many people are you with the Open Days?

E: Our group chat has nine people in it, so with nine students for the bachelor Open Days.

L: For the master Open Days we don’t have a fixed team, but that currently consists of three people.

Do you prepare a lot for the Open Days, and how?

Em: I’ve made a PowerPoint presentation, when I was doing it for the first time. And then I revised the PowerPoint each time a bit. So, not a lot.

J: We’ve all had to do a little open day training of 1 or 2 hours.

Ev: I also had to do that by the way, the Dutch speaking version unfortunately. So I just sat there, preten-

ding I was a very shy person but I didn’t know how to say the things I wanted to say. I knew what was going on, I just couldn’t say anything.

A: I did that training a long time ago, so I forgot that we had that kind of preparation. Now my preparation is mostly watching at the workshop while Lavinia is doing the peptalk. And just improvise a bit.

L: I look for alumni, although they don’t respond often, I also have contact with some teachers. And I make a nice timetable of who has to be where, and order the materials for all the Open Days of EEMCS.

J: I did record once a video for the online Open Days.

L: So he will be the face of Applied Mathematics for the coming five years.

How would you describe your tasks during the Open Days itself?

A: Being social

Text: Jorg Gortemaker and Daan van Kats

Ev: I spend a lot of my time sending students and parents from one location to another. Also for the hosting, I had to say ‘hi’ and point them to the next part of the program.

A: At a normal open day, you have to practise rolling your eyes, since you get the same questions over and over again.

Em: We have made a bingo-card even this year.

L: You also get a bunch of overbearing parents that speak for their children. So we need to know how to engage the child and ignore the parents, in a subtle way.

A: And you really have to be able to explain the difference between ‘Applied/Toegepaste’ and ‘Technica/ Technische’ Mathematics.

L: I also noticed that 90% of the parents really have studied at some technical university, either here or in Delft or Eindhoven. Actual statistics.

What do you think of the audience that comes to the Open Days?

L: Usually the prospective students that come to visit are shy or don’t know what to ask, but to compensate for that they have then extremely overbearing parents.

A: They are shy indeed, but once you go talk with them, you have like half of them who suddenly have a lot of questions and they seem to like you.

J: Or they act like..

Ev: The people who come to Open Days also really look like mathematics students.

A: And a few really don’t look like one, and then you never see them again.

L: I like the prospective students, because they always complement us on how friendly we are.

A: And you also always have those few people that get free from school

and that’s why they are there, and then they realise they don’t know why they chose to go to Applied Mathematics.

J: Or you get forced to go to an open day in Enschede, but you don’t want to study in Enschede at all.

A: But you can have brilliant conversations about what they do want to do.

L: You can be helpful.

Ev: Mostly about how to get a room.

Are you able to spot the students that are going to apply for the study already at the Open Days?

A: Partially yes.

L: To some extent, but when you look at the actual population of AM that we currently have, way less than half of them even did go to an open day. So it is very difficult to guess.

A: But that also is because of the online Open Days of the last few years.

L: But also for older generations, if you ask people around, maybe they have been at an open day at the UT, but not specifically for Applied Mathematics.

What is the first thing you ask people at the Open Days?

Em: “Hello, can I help you?”, “Do you have any questions?”, “How has the open day been so far?”

L: Usually you ask them to which study they went or go to for the other session of the open day.

A: We have a variety of questions with which we can switch around.

L: Or if it is really early in the mor-

ning, and they are already there, you can ask if they came from far.

Em: “How long in the car?”

A: That first question is to make them feel sort of at home and then they later also can open up for us with questions about the study.

L: It could be kind of scary if we just walk up to you and ask like “Did you know that in Module 8 we do this?”.

Does it happen often that things go wrong?

A: Define wrong, since often things don’t go as planned, but from the prospective student-side, I don’t think a lot seems to go wrong.

And how do you fix it if something doesn’t go as planned?

A: I then say “Lavinia!”.

L: It depends, I think that in general our session goes relatively well and according to plan. For the Open Days in general, like catering and stuff, indeed, things don’t go by plan. Also for example the shirts don’t fit for all of us.

What qualities should someone who works at the Open Days have?

A: The social aspect and not being afraid to start small talk and that

kind of stuff.

Ev: Looking approachable, and being able to tell people where the bathroom is.

J: Because they can’t read signs.

A: And it is nice if you do something besides your study, it doesn’t matter in what sense.

Em: Such that it is a bit of an interesting story that you can tell, then you can show that you don’t always study all day long.

L: Usually we ask during interviews active people, who are very social, and show a general good understanding of what the study is and what you can do aside from studying. Also we look for people who like the UT in general, and not only Applied Mathematics. Since if Applied Mathematics appears not to fit, you can maybe guide them to another study within the UT.

A: But in the end, it is for me about letting them make a good choice.

L: Yes you shouldn’t force it, but still be enthusiastic that you are studying here.

Em: Enthusiastic, but still honest, in short.

Do you see the Open Days teams from other studies more as colleagues or as rivals?

A: I think they are friendly rivals.

J: Frenemies.

A: For me, if they have a better picture of what studying Applied Mathematics is. It is nice if in the end they think they wanna study it, I’m also fine with them knowing that this is not the study for them.

Ev: Better knowing early.

J: Reducing the drop-out-rate!

L: I like the fact that they think that we organise things nicely.

Ev: We’re representing the university, and not only the study.

L: But we’re also representing ourselves as a group, and I think that we do that really well.

L: Since being now also busy for the faculty, I now see the teams within EEMCS more on the friendly side. You still want to help eachother out.

A: Sometimes you only play a bit the rival like “Oh, don’t pick our students!” and stuff.

J: You ain’t gonna fight.

Do you try to stand out from the other studies? If so, how?

L: We don’t really concern ourselves with what other studies do.

A: True.

J: We just say “mathematics is really small, you know!”

A: Yes exactly, the “small and family”-part we promote. Also about Abacus.

When would you say are the Open Days a success?

A: When there are muffins.

L: If after the “go or no-go moment”, only a few leave or none at all, I think it was a success. I say this because for example BIT had so many people leaving after this moment.

If you have to describe yourselves as one of the Open Days stickers, which one would it be and why?

L: Have you seen them?

Em: Sorry, I don’t remember them. A: They are all over the Abacus room.

L: It’s called “Stick to the UT”.

A: The sad part is that they don’t stick at all. They fall off everything you stick it on.

L: For me the sunken tower, since

I’m literally barely hanging on these days.

Ev: I wanna be the little robot, he is pretty cute. You see him around all over the place. Also because I’m little, and the newest to the Open Days team.

A: I will go for the brains, because he clearly got his bachelor. I have to say to everyone that I got my bachelor's and still don’t know what I’m going to do with Applied Mathematics.

Em: I will just claim the face.

From Student to Alumnus/a

Text: Diana Dalenoord

Don't turn stragglers into trackers! Update your profile on the alumni portal

Once you have received your degree (BSc or MSc) and left the Applied Mathematics programme, stay in touch. Enter your personal e-mail address on the alumni portal and join the Abacus WhatsApp group.

If your profile is up to date, we can send you fun facts or invite you to alumni events. We can invite you on behalf of the study association Abacus to visit or speak at their symposium. Wouldn't it be nice to come back to campus? If you ensure your private email address is in your profile, you’ll receive the Applied Mathematics & WSG Abacus newsletter.

Another great communication tool is the alumni announcements group chat on WhatsApp which Abacus is starting up. This way, they can inform you in time about interesting events for AM alumni so that you can note the date in your calendar. They will only promote activities which they think will be really interesting for alumni, so no worries about spam! If you are interested in joining this group chat, join via https://bit.ly/Abacus-Alumni-WhatsApp. Stay well-informed about the latest Abacus events for alumni!

Besides the possibility of editing your profile on the alumni portal (via your student number and password), you'll find the latest alumni network news on the alumni pages. You have access to the library where you can use JSTOR for free and browse academic journals, articles, theses and papers. Goodha-

A: No, Jorrit is the face, because he is now the face of Applied Mathematics!

Em: Then I’ll take the heart.

Any last thoughts to share?

A: We have Open Days muffins.

L: The Open Days muffins really taste better than the normal ones from the Waaier. It is weird.

bitz offers free courses in all kinds of fields. So definitely worth taking a look! Via the Network button, you can search for fellow students you have lost track of.

Join Abacus’ WhatsApp group, log in on the alumni portal, update your details via https://bit.ly/LogInAlumni-Portal, follow the messages on LinkedIn Kwadrant via https:// bit.ly/LI-Kwadrant, or send me an e-mail: d.dalenoord@utwente.nl.

The Pen

Text: Jorg Gortemaker

Hello everyone, I would like to use this space to talk about eSports. No, this was not a typo, instead of talking about the Football World Cup I am talking about the CS:GO Rio Major, one of the biggest events in eSports of the past year. I would like to take this page to introduce you to this wonderful eSports event and my personal experience.

So to start of: What is a CS:GO major? It is an event that happens twice a year and winning it is equivalent to winning Wimbeldon in Tennis or winning the Champions league in Football. Teams qualify themselves by playing in regional events and are then seeded according to their ranking. Europe gets most of these spots, some go to North America and what is left over is distributed between Asia, South America and Oceania. At the major there are three stages, the Challenger stage, Legends stage and Champions stage. They are comparable to the preliminary round of the Champions League, the group stage of the Champions league and the knock-out phase of the Champions league respectively. Some teams are directly seeded in the Legends stage and other ours have to fight for a spot in the Challenger stage.

These stages use a very common format for eSports which is the Swiss format. You play matches until you have either won 3 matches, in which case you qualify, or you lose 3 matches, then you will be eliminated. Every match is against a team with the same record, have you won 2 and lost 1, you will be drawn against an opponent who has also won 2 matches and lost 1. This is a great format for ‘Cin-

derella’ stories to happen, teams could lose 2 matches and still have a chance to qualify.

During the major I was rooting for my favourite team, Mouz. They are a German organization and they have had a Dutch player on their team for a long time, they are gone now, but I have stuck with the team. They had to start out in the Challenger stage because the qualification did not go too well for them and a lot of people thought they would bomb out of the tournament. However, against all odds, they managed to win 3 matches and lose none. So with a 3-0 record they had already well exceeded almost everyone’s expectations. The Legends stage

nals. Mouz had to go up against one of the teams with a 3-0 record and a favourite to win the tournament, and somehow they even managed to overcome this battle. Sadly in the Semi-final they lost out to now Major Champions in Outsiders.

I thought they had an amazing run, especially since everyone thought they would not even make it to the second stage. I think that is what makes CS:GO majors so great, they are three weeks of a lot of great matches and even underdogs can make great runs into the tournament. Be sure to check out the next major, which takes place in Paris from the eighth until the 21st of May next year.

started out great with a big 16-2* win over North America’s number one seed Liquid, but then they had a hiccup along the way and despite beating Vitality in a thrilling overtime match, which ended 1917, they had a 2-2 record. If they were to win they would qualify for the Champions Stage, if they lost it would be the end of their tournament. They managed to edge out the other team, Ence, with a 2-1 win (16-5, 8-16, 16-9) and they got to the Champions Stage.

This stage is a simple knock-out phase, starting with the quarter fi-

Fairness of Dice

Text: Emile van der Veer

Introduction

For a really long time now, I have been interested in shapes and dice. These two subjects fit really well together. For example, one can ask themselves which shapes can make ‘fair’ dice. Where we call a die fair if there is equal probability for each number to be the result of a roll of a die. There are a whole bunch of trivial options to obtain such a result, like putting the same number on every face, or making a die with only face. However, this is not really useful if you want an actual physical die.

Symmetries

As it turns out, for a die to be fair, we need certain amounts of symmetry. The easiest option for 3-dimensional shapes with maximal symmetry is to take the five Platonic solids: the tetrahedron, the cube, the octahedron, the dodecahedron and the icosahedron. These five shapes are indeed the most used shapes for dice, with the regular six sided die of course being the cube. However, these five shapes are not the only shapes that could make for fair dice. For example, a coin is a really good example for a two sided die. Although, there is an all so small possibility that the coin will land on its side, making it not completely ‘fair’. In theory we can fix this by making the coin infinitely thin, but this does not really hold up in practice. In practice, it is much easier to define a coin to be a fair two sided die if we simply re-toss the coin if it lands on the side, until it lands on an actual ‘valid’ face. All these shapes could work as fair dice, but these are not the only shapes that could work as fair dice. Actually, all the shapes that fall under the family of the Isohedra can be used to construct fair dice. They do not

have maximal symmetry, but they all have enough symmetry to produce fair dice.

Regular Polyhedra

The platonic solids work as fair dice because they are really symmetrical, they have symmetry over all axes orthogonal to their faces, around all vertices and edges. This makes them regular polyhedra. If we go to 2D, we can very easily find an infinite list of regular polygons (the 2D equivalent of a regular polyhedron), a small example to illustrate this can be found on https://www. geogebra.org/m/jjmxy9xz. Using this we can easily construct the five Platonic solids. However, these five are not the only regular polyhedra,

they are merely the only five regular convex solid polyhedra. If we allow polyhedra that are not solid, we cannot make dice out of them, but theoretically we should be able to make dice out of shapes that are not convex. Deciding which number actually comes up might be a bit tricky, but it should be possible. If we allow this, we are able to add four more regular polyhedra to our list, namely the Kepler-Poinsot polyhedra. A nice video about this can be found on the YouTube channel jan Misali, and is titled “there are 48 regular polyhedra”.

Conclusion

Most of the time, the dice that are made are cubic dice, but quite

some games need a four-sided, eight-sided, ten-sided, twelve-sided, twenty-sided and onehundredsided dice as well. These are often made using the Platonic solids and two pentagonal trapezohedra. But we could also construct fair dice out of a whole lot of other shapes in the Isohedral family. And there actually are dice made out of these shapes, this has allowed people to make dice with ‘weird’ amount of faces, like a 5 sided die, or a 30 sided die. But other examples of dice have also been made that aren’t even in the family of Isohedral figures that rely on different kinds of rules on what counts as a die. You could for example make a prism out of a regular polygon and only roll it over the axis connecting the middlepoints of the regular polygons. This is not a shape that is part of the Isohedral family, but it would still make for a perfectly fine die. And then you can also look at a whole bunch of other factors that determine how fair a die is, like the

Your Story

Text: Xanti Lizanzu

This ‘Your Story’ will be a ‘My Story’ this time because I wanted to write a piece about the student for a day program. I have been a mentor for this program for a year and I wanted to share the experience with you guys. A year has been more than enough for me, but during that year I noticed some aspects of the program that truly intrigued me.

The first of them is by telling people with little knowledge about the study. It made me think about the whole study, as well as the different courses. For example, when trying to explain what Linear Structures is about to someone who does not

weight distribution and the number configuration on the dice, but most of these can be considered to not produce significantly different re-

sults unless one makes the die unfair on purpose.

know any linear algebra, it makes you think about what it actually is. For me, this realization did not happen when following the course, because I was too focused on the assignments I made every day. I liked the fact that the new students made me see the bigger picture.

Next to that, new students also question things that I deem trivial. For example: what is the division between theoretical and applied mathematics? For me, this division is a given. For students who do not study here yet, it is not. Thinking about questions like that makes me form my own opinion about the study and university even better.

It is also somewhat related to the argument made in the previous paragraph.

A last and final aspect I noticed I liked is that enthusiastic new students make me also re-spark my love for mathematics. New students are (most of the time) very interested in the subjects they encounter. This enthusiasm and curiosity are truly contagious.

In no way this is a promotion to join the student for a day program. I simply hope you frequently think about what made you choose this study and remember what an interesting bachelor we are following.

Review: House of Earth and Blood (Crescent City 1)

Text: Marieke Snoeren

“Excuse me while I ugly cry.” – Me, while reading the last 200 pages.

Like a real book lover, I cannot possibly choose a favourite book, however this one is for sure in my top 10. Having close to 800 pages this book looks quite intimidating, but once I started reading I wished I cloud keep turning the pages and never reach the end. Luckily for all of us, the sequel is now out and it is arguably better than the first one. Although I have not yet finished the second book… yet.

I am getting ahead of myself. Let me first tell you what this book is about. We follow the strong female lead named Bryce in her journey to survive in a world where her dearest friends are brutally murdered, under which her best friend Danika. Bryce will do anything to avenge their deaths. Together with Hunt, a fallen angel aka the love interest, she discovers the many secrets Danika kept in order to protect the world and the dark scheme of the Archangel of Crescent City.

Of course, a good book is incomplete without the death of your favourite character. The death of the lazy

Puzzle: Secret Recipe

Text: Tim Hut

After the passing of your greatgreat-grandmother, she left you her two favourite chickens and the recipe for her famous apple-pie. When trying to recreate it, you realise that four of the ingredients are written in code. You know however that your great-great-grandmother was well versed in binary and using the ASCII table and couldn’t grasp anything more difficult than onetime pad encryption. Furthermore you know that she was always very forgetful and would not remember

gossip queen was the beginning of the end. Read: where I started crying.

“I am descendent of Ranthia Drahi, Queen of Embers. She is with me now and I am not afraid. My friends are behind me and I will defend them.”

The world building in this book is absolutely marvellous. Every detail has a purpose, however you only realise that towards the end of the book. The beginning of the book was definitely wearisome, but it was so so so worth it.

For me this book is the perfect example of high fantasy in a modern world with a tiny bit of romance. The book has multiple points of views, but you mainly read Bryce’s. Even though we read from Bryce’s perspective we do not know all her secrets, which makes some reveals even more shocking and heart-breaking. The writing style is easy to read, the perfect balance between humour and solemnity with sentences raging from “Immortality is a long time to have a giant stick up your

ass” to “The angel’s gaze met hers, so full of agony she thought it was what her soul must look like”.

In summary this book was absolutely incredible. A little hard to get into but 100% worth it.

5/5 stars 4/5 tears

more than a single key of 32 bits (therefore the encryption is not perfectly secret). Can you decrypt the final four ingredients?