Program Definition flip_Irreflexive `(Irreflexive R) : Irreflexive (flip R) :=
      irreflexivity (R:=R).Program Definition flip_Symmetric `(Symmetric R) : Symmetric (flip R) :=
      fun x y H => symmetry (R:=R) H.Program Definition flip_Asymmetric `(Asymmetric R) : Asymmetric (flip R) :=
      fun x y H H' => asymmetry (R:=R) H H'.Program Definition flip_Transitive `(Transitive R) : Transitive (flip R) :=
      fun x y z H H' => transitivity (R:=R) H' H.

Lemma flip_PER `(PER R) : PER (flip R).