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Dear Dirichlet,

My brother has travelled to We llington for a few months while he works for a client. As we usually see him most we ekends, I think the kids will mis s him a lot. I know we could always videocall, but is there an easier way for us to see him?

— Torquil Farquhar de Smith, Fraoch

y Bay, Scotland

DIRICHLET SAYS: You are fortunate that he has moved to New Zealand.

Pop into your local Waterstones and pick up an antipodal map (shouldn’t be more than £l0). If you take a short walk to northern Spain (about 500 miles, and 500 more), you should be able to apply the map there. Bob’s your uncle: in the projection space you’ll be together. Warning: this projection ends up flooding most of the world.

Dear Dirichlet,

and we have always ghbour Ian for a few years now, I have lived next door to my nei relenta new BMW and since then has ght bou he , ago s nth mo two But got on well. y to tell him to my aging hatchback. I’d like a wa of te sta the on d nte me com lessly tful response? me miserable. Any tips for a tac stop his mocking, as it’s making

— Plotting something, West Ruislip

 DIRICHLET SAYS: Clearly you’ve reached the point where you need to draw the line and coordinate an attack on this unfriendly fellow. Take some axes to his right hand while shouting “SPATIAL DELIVERY”. That ought to be plain enough for Car-tease-Ian. (Apologies for the graphic nature of my response.)

Dear Dirichlet,

I am a badger. Last night I spent a very cold night in the forest, as I arrived home to find I couldn’t get in. I would like to avoid this happening again. What should I do?

— Badger, Hemel Hempstead

DIRICHLET SAYS: Your sett A will be open if x ϵ A, ε > 0 s.t. Bε (x) ϲ A.



More Dear Dirichlet, including two exclusive collections, online at 25

spring 2016

Chalkdust, Issue 03  

Popular mathematics magazine from UCL

Chalkdust, Issue 03  

Popular mathematics magazine from UCL