MathDB

Question 6

Source: Iran TST 2006

April 18, 2006

inductioncombinatorics proposedcombinatorics

Problem Statement

Let

G

be a tournoment such that it's edges are colored either red or blue. Prove that there exists a vertex of

G

v

with the property that, for every other vertex

u

there is a mono-color directed path from

v

u