| a ∈ x0, ∀ m, a. # x0 = m + 1 ∧ a ∈ x0 → #(x0 -1l a) = m ∨ x0 = [] ⊦ 1 + #(x0 -1l a) = # x0, a = a0 |
a ∈ x0, ∀ m, a. # x0 = m + 1 ∧ a ∈ x0 → #(x0 -1l a) = m ∨ x0 = [] ⊦ 1 + #(x0 -1l a) = # x0, a = a0, x0 = []
Used simplifier rules: del1-e: ⊦ [] -1l a = [];% ⊦ # [] = 0; (s)% ⊦ ¬ a ∈ []; (s) Used formulas: x0 = []