# s = 2, s ⊆ s0 ⊦ s.butmin.min ∈ s0
Used simplifier rules: bmin-two-07: ⊦ # s = 2 → s.butmin ≠ ∅;%min-sub: ⊦ ¬ s.min ∈ s0 → (s ⊆ s0 ↔ s = ∅);