Lipschitz and Wadge binary games in second order arithmetic

Abstract

We present a detailed formalization of Lipschitz and Wadge games in the context of second order arithmetic and we investigate the logical strength of Lipschitz and Wadge determinacy, and the tightly related Semi-Linear Ordering principle, for the first levels of the Hausdorff difference hierarchy in the Cantor space. As a result, we obtain characterizations of WKL0 and ACA0 in terms of these determinacy principles. Keywords: Reverse mathematics, Determinacy, Wadge games, Semilinear Ordering principle