| ⌜m⌝ < # nσ, stutf(nσ), n ≤ nσ[m] ⊦ ∃ m0. m0 ≤ m ∧ nσ[m0] = n |
⌜m0 +1⌝ < # nσ, stutf(nσ), n ≤ nσ[m0 +1], ∀ nσ, n. ⌜m0⌝ < # nσ ∧ stutf(nσ) ∧ n ≤ nσ[m0] → (∃ m1. m1 ≤ m0 ∧ nσ[m1] = n) ⊦ ∃ m1. m1 ≤ m0 +1 ∧ nσ[m1] = n
Used simplifier rules: stutf-zero: ⊦ stutf(nσ) → nσ[0] = 0;%nat freely generated by 0, +1;;% ⊦ m ≤ 0 ↔ m = 0; (s)% ⊦ ⌜0⌝ < # nσ ↔ nσ ≠ []; (s)