Complete graphs 1Discrete Mathematics Level 3
Each of the edges of a complete graph with 9 vertices is coloured either blue or red. There either there exist x vertices with all the edges connecting them blue, or y vertices with all the edges connecting them red.
Find the maximum value of x + y
Details - In the mathematical field of graph theory, a complete graph is a simple undirected graph in which every pair of distinct vertices is connected by a unique edge.