Problem A. 523. (December 2010)

A. 523. There are given a simple graph and a positive integer n. Show that there are two, not necessary distinct vertices a and b in the graph for which the number of directed walks of length n, starting point a and end-point b, is even.

(5 pont)

Deadline expired on January 10, 2011.

Statistics:

8 students sent a solution.
5 points:	Ágoston Tamás, Backhausz Tibor, Frankl Nóra, Janzer Olivér, Nagy 235 János, Nagy 648 Donát, Strenner Péter.
1 point:	1 student.

Problems in Mathematics of KöMaL, December 2010