On homotopy exponentials in path categories

Abstract

In the first part of this paper we show that path categories are enriched over groupoids, in a way that is compatible with a suitable 2-category of path categories. In the second part we introduce a new notion of homotopy exponential and homotopy Pi-type for path categories, the strong homotopy exponential and the strong homotopy Pi-type. We prove some of their basic properties, along with two important technical propositions. The results in the second part of this paper are mostly obtained using the groupoid enrichment of path categories established in the first part.