proposition: Fact poly_arr_eq_eq {s t} : s = t -> poly_arr s s = poly_arr t t.
proof: Proof. by move=> ->. Qed.
imports: List Lia Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Util(Facts poly_type_facts pure_term_facts term_facts typing_facts pure_typing_facts pure_typable_prenex) ssreflect ssrbool ssrfun