proposition: Lemma rt_seq_swap r r' : (r ⨾ r') ＊ ⨾ r ≡ r ⨾ (r' ⨾ r) ＊.
proof: Proof. by rewrite !rtE; autorewrite with hahn hahn_full; rewrite ct_seq_swap. Qed.
imports: Program.Basics Arith micromega.Lia Permutation List Setoid HahnBase HahnList HahnRelationsBasic HahnSets