| 〈build_rec#(i + 1; x2, to2)〉 (x2 = x3 ∧ to2 = fail), 〈build_rec#(i + 1; x, to2)〉 (x = x2 ∧ to2 = some(t0)), ∀ j0, i0, x, x0, to. i→n(j0 - i0) < i→n(i1) → (x = x0 ∧ x0 ≠ [] ∧ i0 ≤ j0 ∧ max(x0) ≤ j0 → 〈build_rec#(i0; x, to)〉 (to = fail → (∀ t, x1. x0 ≠ depths(t, i0) + x1))), x = depths(t0, i + 1) + x2, to2 = fail, (depths(t1, i + 1) + depths(t2, i + 1)) + x1 = depths(t0, i + 1) + x2, d ∈ depths(t1, i + 1), max(depths(t0, i + 1) + x2) ≤ i1 + i, i < d, 0 ≤ i1, d ∈ depths(t0, i + 1), ∀ t, x. x2 ≠ depths(t, i + 1) + x ⊦ |
⊦ depths(t0, i) + x = depths(t1, i) + y ↔ x = y ∧ t0 = t1
〈build_rec#(i + 1; x, to2)〉 (x = x2 ∧ to2 = some(t0)), 〈build_rec#(i + 1; x2, to2)〉 (x2 = x3 ∧ to2 = fail), ∀ j0, i0, x, x0, to. i→n(j0 - i0) < i→n(i1) → (x = x0 ∧ x0 ≠ [] ∧ i0 ≤ j0 ∧ max(x0) ≤ j0 → 〈build_rec#(i0; x, to)〉 (to = fail → (∀ t, x1. x0 ≠ depths(t, i0) + x1))), x = depths(t0, i + 1) + x2, to2 = fail, depths(t2, i + 1) + x1 = x2 ∧ t1 = t0, d ∈ depths(t1, i + 1), max(depths(t0, i + 1) + x2) ≤ i1 + i, i < d, 0 ≤ i1, d ∈ depths(t0, i + 1), ∀ t, x. x2 ≠ depths(t, i + 1) + x ⊦
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ i + j = j + i], [CSIMPSEQ : ⊦ (x + y) + z = x + y + z])], [EXTRATERMS : (x2, t0, depths(t2, i + 1) + x1, i + 1, t1)]]