| n ≤ # str0, ∀ n0. n0 < # str0 → pos(s→l(str0)[n0], str0) = n0 ∨ str0 = "" ⊦ char ' + str0 = "", n = 0, pos(s→l(str0)[n - 1], char ' + str0) = n, dups(s→l(str0)), char ∈ s→l(str0) |
n = m + 1, n ≤ # str0, ∀ n0. n0 < # str0 → pos(s→l(str0)[n0], str0) = n0 ∨ str0 = "" ⊦ char ' + str0 = "", n = 0, pos(s→l(str0)[m], char ' + str0) = n, dups(s→l(str0)), char ∈ s→l(str0)
Used simplifier rules: n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: n, m