How to program a never-losing chess engine

This article proposes a model, based on graph theory, to represent a variety of two-player games of perfect information, such as chess and checkers. I then provide a backtracking minimax algorithm to find, if it exists, a perfect game strategy (game resolution), and subsequently a variant of that algorithm which is required to determine a weaker condition: the existence of a strategy to never lose (always reach at least a draw). Of course, this does not mean that in practice the algorithm can find such a strategy in a short time, but here we are only concerned with formally proving that this is possible, at least theoretically.