| a ∈ x0, ∀ m0, a1. # x0 = m0 + 1 ∧ a1 ∈ x0 → #(x0 \ a1 ') = m0 ∨ x0 = [] ⊦ 1 + #(x0 \ a ') = # x0, dups(x0), a0 ∈ x0 |
a ∈ x0, ∀ m0, a1. # x0 = m0 + 1 ∧ a1 ∈ x0 → #(x0 \ a1 ') = m0 ∨ x0 = [] ⊦ 1 + #(x0 \ a ') = # x0, x0 = [], dups(x0), a0 ∈ x0
Used simplifier rules: diff-e: ⊦ [] \ y = [];% ⊦ # [] = 0; (s)% ⊦ ¬ a ∈ []; (s) Used formulas: x0 = []