fact: Definition add_om phi := ax_om1 → ax_om2 → phi.
imports: Undecidability.FOL(Syntax.Facts Semantics.Tarski.FullFacts Deduction.FullNDFacts) Undecidability.FOL.Sets(ZF) Undecidability.FOL.ZF Lia Undecidability(Shared.ListAutomation)