On bi-enriched $\infty$-categories

Abstract

We extend Lurie's definition of enriched $\infty$-categories to notions of left enriched, right enriched and bi-enriched $\infty$-categories, which generalize the concepts of closed left tensored, right tensored and bitensored $\infty$-categories and share many desirable features with them. We use bi-enriched $\infty$-categories to endow the $\infty$-category of enriched functors with enrichment that generalizes both the internal hom of the tensor product of enriched $\infty$-categories when the latter exists, and the free cocompletion under colimits and tensors. As an application we prove an end formula for morphism objects of enriched $\infty$-categories of enriched functors and compute the monad for enriched functors. We build our theory closely related to Lurie's higher algebra: we construct an enriched $\infty$-category of enriched presheaves via the enveloping tensored $\infty$-category, construct transfer of enrichment via scalar extension of bitensored $\infty$-categories, and construct enriched Kan-extensions via operadic Kan extensions. In particular, we develop an independent theory of enriched $\infty$-categories for Lurie's model of enriched $\infty$-categories.