fact: Parameter flatten_cf : forall f t1 t2, arity f = AC -> well_formed_cf t1 -> well_formed_cf t2 -> permut (flatten f (t1 :: nil)) (flatten f (t2 :: nil)) -> t1 = t2.
imports: Coq(Relations List Arith Morphisms) CoLoR(more_list list_permut list_sort term_spec term_o equational_theory_spec equational_theory)