fact: Definition Ut' d t := many_poly_arr [poly_arr (to_d' d t) (poly_var (d+b1t)); poly_arr t (poly_var (d+b2t))] (poly_var (d+ut)).
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