proposition: Lemma or8_equiv: forall A1 A2 A3 A4 A5 A6 A7 A8 , or8 A1 A2 A3 A4 A5 A6 A7 A8 <-> A1 \/ A2 \/ A3 \/ A4 \/ A5 \/ A6 \/ A7 \/ A8 .
proof: Proof. intros. split. intros H. rewrite <- or7_equiv. destruct H. constructor 1. exact H. constructor 2. exact H. constructor 3. exact H. constructor 4. exact H. constructor 5. exact H. constructor 6. exact H. constructor 7. left. exact H. constructor 7. right. exact H. intros H. destruct H. constructor 1. exact H. rewrite <- or7_equiv in H. destruct H. constructor 2. exact H. constructor 3. exact H. constructor 4. exact H. constructor 5. exact H. constructor 6. exact H. constructor 7. exact H. constructor 8. exact H. Qed.
imports: Coq(Setoid Morphisms)