| st.keys.min < a, st.keys.min ∈ st ⊦ st[a, d].keys.min = st.keys.min, st[a, d] = ∅, st = ∅ |
st.keys.min < a, st.keys.min ∈ st ⊦ (st.keys ++ a).min = st.keys.min, st = ∅
Used simplifier rules: insert-03: ⊦ st[a, d].keys = st.keys ++ a;% ⊦ st[a, d] ≠ ∅; (s)