| n < # x ⊦ #(x \ x[n] ') = # x - 1, x = [], dups(x) |
# x = m + 1 ∧ # x ≠ 0, n < # x ⊦ #(x \ x[n] ') = m, x = [], dups(x)
Used simplifier rules: l: ⊦ # x = 0 ↔ x = []; from specification list-data%n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: # x, m