fact: Variables (a0 b0: nat).
imports: ZArith List PeanoNat Lia Relations.Relation_Operators Relations.Operators_Properties Undecidability.MinskyMachines.MM2 Undecidability.CounterMachines.Util.CM1_facts Undecidability.MinskyMachines.Util.MM2_facts ssreflect ssrbool ssrfun