Title: Costability of Comodules

Abstract: Given a ring $R$, we have a classical result stating that the ordinary category of modules is the abelianization of the category of augmented $R$-algebras. Analogously, using the framework of infinity categories and higher algebra, Francis showed that the infinity category of $R$-modules is the {\em stabilization} of the infinity category of augmented $R$-algebras. In this work we show a dual result for coalgebras over a cooperad $Q$: namely that given a coalgebra $C$, comodules over $C$ are the costabilization of coalgebras over $C$, which is the universal stable category with a finite colimit preserving functor to coalgebras over $C$.