lean4-htt/tests/lean/run/def14.lean
2020-10-25 09:16:38 -07:00

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inductive Formula
| eqf : Nat → Nat → Formula
| impf : Formula → Formula → Formula
def Formula.denote : Formula → Prop
| eqf n1 n2 => n1 = n2
| impf f1 f2 => denote f1 → denote f2
theorem Formula.denote_eqf (n1 n2 : Nat) : denote (eqf n1 n2) = (n1 = n2) :=
rfl
theorem Formula.denote_impf (f1 f2 : Formula) : denote (impf f1 f2) = (denote f1 → denote f2) :=
rfl