(λ n. (n < # x ⊃ x[n];nf(n - # x))) = (λ n. (n < # x ⊃ x[n];nf0(n - # x))) ⊦ nf = nf0
Used simplifier rules: ⊦ ⌜nf⌝ = ⌜nf0⌝ ↔ nf = nf0; (s)