proposition: Fact term_size_ren_term {ζ ξ P} : term_size (ren_term ζ ξ P) = term_size P.
proof: Proof. elim: P ζ ξ => /=; by congruence. Qed.
imports: List Lia Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Autosubst.unscoped Undecidability.SystemF.Util(Facts poly_type_facts pure_term_facts) ssreflect ssrbool ssrfun