| s ∩ (s0 ++ a) = ∅, a ∈ s ⊦ |
a ∈ s, a0 ∈ s, ∀ a0. ¬ a0 ∈ s ∨ ¬ a0 ∈ s0 ++ a ⊦
Used simplifier rules: Intersect: ⊦ a ∈ s1 ∩ s2 ↔ a ∈ s1 ∧ a ∈ s2;%int-a: ⊦ (s ∩ s0) ∩ s1 = s ∩ s0 ∩ s1;%ne-01: ⊦ a ∈ s → s ≠ ∅; (forward) from specification set-basic% ⊦ ¬ a ∈ ∅; (s)% ⊦ s1 = s2 ↔ (∀ a. a ∈ s1 ↔ a ∈ s2); (s)