proposition: Lemma permut_get_8 : forall l1 l2 l3 l4 l5 l6 l7 l8 l9, (l1 \u l2 \u l3 \u l4 \u l5 \u l6 \u l7 \u l8 \u l9) = (l2 \u l3 \u l4 \u l5 \u l6 \u l7 \u l8 \u l1 \u l9).
proof: Proof. Proof using. intros. do 2 rewrite (union_assoc l2). apply permut_get_7. Qed.
imports: TLC(LibTactics LibLogic LibReflect LibRelation LibList LibInt LibNat LibOperation LibEpsilon LibSet LibMonoid)