Exponentiable functors between synthetic $\infty$-categories
César Bardomiano-Martínez
TL;DR
This work develops a synthetic theory of exponentiable functors between $(\infty,1)$-categories inside $sHoTT$, introducing Segal type completion as a universal way to complete a type to a Segal type and proving a Conduché-style criterion for exponentiability at the Segal-type level. It specializes the criterion to Rezk types and demonstrates semantic alignment with the standard bisimplicial-set model, establishing soundness of the synthetic definitions. The paper also connects exponentiable functors to profunctor composition via a coend-like construction and discusses the limits of encoding correspondences in $sHoTT$, identifying directions for future refinement. Overall, it provides a foundational framework for internal exponentiation in synthetic higher category theory and links these notions to established $\infty$-categorical results.
Abstract
We study exponentiable functors in the context of synthetic $\infty$-categories. We do this within the framework of simplicial Homotopy Type Theory of Riehl and Shulman. Our main result characterizes exponentiable functors. In order to achieve this, we explore Segal type completions. Moreover, we verify that our result is semantically sound.
