| a ∈ x0, ∀ m, a1. # x0 = m + 1 ∧ a1 ∈ x0 → #(x0 \ a1 ') = m ⊦ x0 = [], #(x0 \ a ') + 1 = # x0, dups(x0), a0 ∈ x0 |
Used simplifier rules: lels-01: ⊦ ¬ m ≤ n ↔ n < m; from specification nat%one-01: ⊦ m < 1 ↔ m = 0; from specification nat-basic1%l: ⊦ # x = 0 ↔ x = []; from specification list-data%eq-02: n ≤ m ⊦ (m - n) + n0 = n1 ↔ m + n0 = n + n1; from specification nat%c: ⊦ m + n = n + m; from specification nat-basic2%a: ⊦ (m + n0) + n1 = m + n0 + n1; from specification nat-basic2 Used terms: # x0 - 1, a