WORKED EXAMPLE 1.26
Draw two non-isomorphic graphs that both have degrees 1, 1, 1, 1, 2, 2, 4 .
EXERCISE 1C
Which of these graphs are planar?
SA
M
1
PL E
These trees each have degrees 1, 1, 1, 1, 2, 2, 4 , but in the first the vertex of degree 4 is connected to two of degree 2 and two of degree 1, while in the second the vertex of degree 4 is connected to one of degree 2 and three of degree 1.
2
Which of these graphs are isomorphic? A
B
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