⊦ s ≠ ∅ → s.min ∈ s
Used simplifier rules: ⊦ s -- a = ∅ ↔ s = ∅ ∨ s = ∅ ++ a; (ws)% ⊦ a ∈ s -- b ↔ a ≠ b ∧ a ∈ s; (ws) Used terms: s -- s.min