fact: Definition M_opair x y := ({{x; x}; {x; y}}).
imports: Undecidability.FOL(Syntax.Facts Semantics.Tarski.FullFacts FST) Undecidability.FOL(Sets.FST) Undecidability.FOL.TRAKHTENBROT(hfs) Undecidability.Shared.Libs.DLW.Utils(finite) Undecidability(Shared.ListAutomation) Coq(Lia)