fact: Fixpoint is_safe_poly_type (n: nat) (t: poly_type) := if t is poly_abs t then is_safe_poly_type (1+n) t else is_safe_poly_arr n t.
imports: PeanoNat List Lia Undecidability.SystemF.SysF Undecidability.SystemF.Autosubst.syntax Undecidability.SystemF.Util(Facts poly_type_facts term_facts typing_facts iipc2_facts sn_facts) Undecidability.DiophantineConstraints.H10C ssreflect ssrbool ssrfun