How to pick your team with no size restriction

Abstract

Settling a problem raised by Eccles in 2015, Narayanan in 2026 considers a two-player game in which two captains alternately select players while the opponent decides to which team each selected player is assigned. Moreover, the two teams are required to have equal cardinalities, and Narayanan proved that the second player has a non-losing strategy. In this paper, we study a natural variant in which the teams are allowed to have different cardinalities, and the winner is determined by comparing the average strengths of the two teams. We show that, in this setting, the parity of the total number of players completely determines which player has a non-losing strategy: the first player has a non-losing strategy when the number of players is even, while the second player has a non-losing strategy when it is odd.