fact: Fixpoint df_size_Z f := (match f with | df_cst _ _ => 3 | df_eq _ _ => 3 | df_op _ _ _ _ => 5 | df_bin _ f g => 1 + df_size_Z f + df_size_Z g | df_exst f => 1 + df_size_Z f end)%Z.
imports: Arith Nat ZArith Lia Undecidability.Shared.Libs.DLW.Utils(utils_tac gcd sums bounded_quantification)