fact: Fixpoint size_exp {Z} (s: exp Z) := match s with | var _ => 0 | const c => 0 | app s t => S (size_exp s + size_exp t) | lambda s => S (size_exp s) end.
imports: List Lia Program.Program Undecidability.HOU(std.std axioms) RelationClasses Morphisms Init.Wf Init.Nat Setoid Undecidability.HOU(calculus.calculus second_order.goldfarb.encoding) FinFun Coq.Arith.Wf_nat