 Homework 3DetailsWrite a complete proof for problem 1.4.2.5.
Hint: Let v be an arbitrary vertex with degree d
and consider the edges (v,v_{i}) for i=1,...d, where
v_{i} are the neighbors of v. If each of these edges
are on an odd number of cycles, you should be able to argue that d is even,
at which point we use a theorem from the book to conclude the graph is Eulerian.
