⊦ mon<(nσ) ↔ (∀ n. ⌜n⌝ + ⌜1⌝ < # nσ → nσ[n] < nσ[n + 1])
mon<(⌜nnf⌝ ) ⊦ ∀ n0. ⌜n0⌝ + ⌜1⌝ < # ⌜nnf from n⌝ → ⌜nnf from n⌝ [n0] < ⌜nnf from n⌝ [n0 + 1]
Used terms: ⌜nnf from n⌝