fact: Definition eq_ex2_rect {A : Prop} {P Q : A -> Prop} {u v : exists2 a : A, P a & Q a} (R : u = v -> Type) (f : forall p q r, R (eq_ex2 u v p q r)) : forall p, R p := fun p => rew <- eq_ex2_eta p in f _ _ _.
imports: Notations Ltac