| x1[m0] = x2 .last, (r ' + x1)[# x2] = x1[m0], # x2 ≤ m0, m0 < # x1, # x2 < # x1, reachable-n(H, # x2, r, x1[m0]), path(r ' + x2, H), path(r ' + x1, H) ⊦ x2 = [], x1 = [], path(r ' + firstn(m0 + 1, x1) + restn(m0 + 1, x1), H), path(r ' + firstn(m0 + 1, x1), H) |
⊦ n ≤ # x0 → firstn(n, x0) + restn(n, x0) = x0
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ m + 1 ≤ n ↔ m < n], [CSIMPSEQ : ⊦ ¬ m < n ↔ n ≤ m], [CSIMPSEQ : ⊦ m < n → (n ≤ m ↔ false)], [CSIMPSEQ : ⊦ (m + n0) + n1 = m + n0 + n1], [CSIMPSEQ : ⊦ m + n = n + m])], [EXTRATERMS : (x1, m0 + 1)]]