Exact, left exact, and right exact functors

Corollary 4.2.27. A functor \(F\colon C \to D\) between stable \(\infty \)-categories is exact if and only if it is left exact if and only if it is right exact: we have equalities \[ \Fun ^{\ex }(C,D) \quad = \quad \Fun ^{\lex }(C,D) \quad = \quad \Fun ^{\rex }(C,D) \] as full subcategories of \(\Fun (C,D)\).