Homotopic distances and group-like spaces

Abstract

Homotopic distance is a numerical homotopy invariant that quantifies the homotopic distinction between two or more continuous maps. In this paper, we look at various versions of homotopic distance between maps and study them on maps to group-like spaces and CW H-spaces. In particular, (1) we develop the theories of probabilistic and diagonalized versions of the homotopic distance and compare their properties, and (2) we show that all versions of the homotopic distance can be calculated precisely in terms of their respective versions of the Lusternik-Schnirelmann category when group-like spaces or CW H-spaces are involved. Our results are refined in the setting of rational groups. On the way, we also study loopings of maps and the nilpotency of the set of homotopy classes of maps to group-like spaces.