fact: Definition hfiber_functor_sigma {A B} (P : A -> Type) (Q : B -> Type) (f : A -> B) (g : forall a, P a -> Q (f a)) (b : B) (v : Q b) : (hfiber (functor_sigma f g) (b; v)) <~> {w : hfiber f b & hfiber (g w.1) ((w.2)^ # v)}.
imports: HoTT.Basics Types.Arrow Types.Paths