proposition: Theorem EqDec_pair_l : forall (A B : Set)(eqd : EqDec (A * B))(b : B), EqDec A.
proof: Proof. intuition. exists (fun a1 a2 => eqb (a1, b) (a2, b)). intuition. rewrite eqb_leibniz in H. inversion H; intuition. subst. eapply eqb_refl. Qed.
imports: FCF.Comp FCF.Rat FCF.Fold List FCF.Blist micromega.Lia FCF.StdNat FCF.NotationV1 FCF.EqDec