fact: Definition hfiber_diagonal {X Y : Type} (f : X -> Y) (p : Pullback f f) : hfiber (diagonal f) p <~> ((p.1 ; p.2.2) = (p.2.1 ; idpath) :> hfiber f (f p.2.1)).
imports: HoTT.Basics HoTT.Types HFiber PathAny Cubical.PathSquare Diagrams.CommutativeSquares