| # s - 1 = 0, 2 < # s, a ∈ s, a0 ∈ s, ∀ a0. a0 = a ∨ ¬ a0 ∈ s, ∀ a0. a0 = b ∨ a0 = a ∨ ¬ a0 ∈ s ⊦ b ≠ a ∧ b ∈ s |
Used simplifier rules: f: ⊦ m < n → n ≠ 0; from specification nat-basic1%size-one-02: ⊦ # s = 1 ∧ a ∈ s ∧ b ∈ s → a = b; (forward) from specification set-basic%f: ⊦ m < n → n ≠ 0; (forward) from specification nat-basic1%lf-01: ⊦ m < n ∧ n = n0 → m < n0; (forward) from specification nat-basic1%n ≠ 0 ⊦ m = n - 1 ↔ n = m + 1; (elim) Used terms: # s, m