fact: Parameter flatten_build : forall f l, arity f = AC -> (forall t, In t l -> match t with | Var _ => True | Term g _ => f <> g end) -> permut (flatten f ((build f l) :: nil)) l.
imports: Coq(Relations List Arith Morphisms) CoLoR(more_list list_permut list_sort term_spec term_o equational_theory_spec equational_theory)