Graph and degree of vertices - IMO LongList 1992 USA3
Source:
September 2, 2010
combinatoricsgraph theoryExtremal Graph TheoryIMO ShortlistIMO Longlist
Problem Statement
Given a graph with vertices and a positive integer that is less than , prove that the graph contains a set of vertices in which the difference between the largest degree of any vertex in the set and the smallest degree of any vertex in the set is at most