Contextually indexed contextual categories

Abstract

In this paper, we define a generalization of indexed categories and contextual categories which we call contextually indexed (contextual) categories. While contextual categories are models of ordinary type theories, contextually indexed (contextual) categories are models of indexed type theories. We also define type-theoretic semi-fibration categories which generalize type-theoretic fibration categories. Every model category in which cofibrations are stable under pullbacks is a type-theoretic semi-fibration category. We show that type-theoretic semi-fibration category gives rise to a contextually indexed contextual category with finite limits. Finally, we prove that the category of simplicial sets with the Joyal model structure gives rise to a locally small Cartesian closed contextually indexed contextual category with indexed limits and colimits.