proposition: Lemma permut_get_7 : forall l1 l2 l3 l4 l5 l6 l7 l8, (l1 \u l2 \u l3 \u l4 \u l5 \u l6 \u l7 \u l8) = (l2 \u l3 \u l4 \u l5 \u l6 \u l7 \u l1 \u l8).
proof: Proof. Proof using. intros. do 2 rewrite (union_assoc l2). apply permut_get_6. Qed.
imports: TLC(LibTactics LibLogic LibReflect LibRelation LibList LibInt LibNat LibOperation LibEpsilon LibSet LibMonoid)