| ⊦ (a0 ∈ st -- a ∧ ¬ a0 ∈ s ↔ a0 ≠ a ∧ a0 ∈ st ∧ ¬ a0 ∈ s) ∧ (a0 ∈ st -- a ∧ ¬ a0 ∈ s → (st -- a)[a0] = ((st \ s) -- a)[a0]) |
⊦ (¬ a0 ∈ s → a0 ∈ st -- a → a0 ≠ a ∧ a0 ∈ st) ∧ (a0 ∈ st -- a ∧ ¬ a0 ∈ s → (st -- a)[a0] = ((st \ s) -- a)[a0])
Used simplifier rules: ⊦ a ∈ st -- b ↔ a ≠ b ∧ a ∈ st; (ws)