On strong avoiding games

Abstract

Given an increasing graph property F , the strong Avoider-Avoider F game is played on the edge set of a complete graph. Two players, Red and Blue, take turns in claiming previously unclaimed edges with Red going first, and the player whose graph possesses F first loses the game. If the property F is “containing a fixed graph H ”, we refer to the game as the H game. We prove that Blue has a winning strategy in two strong Avoider-Avoider games, P 4 game and CC > 3 game, where CC > 3 is the property of having at least one connected component on more than three vertices. We also study a variant, the strong CAvoider-CAvoider games, with additional require-ment that the graph of each of the players must stay connected throughout the game. We prove that Blue has a winning strategy in the strong CAvoider-CAvoider games S 3 and P 4 , as well as in the Cycle game, where the players aim at avoiding all cycles.