∀ b0. b0 ∈ s → b0 < b ⊦ ¬(∀ b0. b0 = a ∨ b0 ∈ s → b0 < b) ↔ ¬ a < b
Used simplifier rules: Greater: ⊦ s < a ↔ (∀ b. b ∈ s → b < a);%rax: ⊦ a ∈ s ++ b ↔ ¬ ¬(a = b ∨ a ∈ s); from specification set-basic