∀ a. ¬ a ∈ st0 ⊦ st0 = ∅
Used simplifier rules: Size-empty: ⊦ # ∅ = 0;%empty: ⊦ # st = 0 ↔ st = ∅;%In-empty: ⊦ ¬ a ∈ ∅;