| a2 ∈ st[a, d], a2 ∈ st0[a, d], st ⊆ st0 ⊦ st[a, d][a2] = st0[a, d][a2], a2 = a0, a2 = a1 |
Used simplifier rules: At-same: ⊦ st[a, d][a] = d;%At-other: ⊦ a ≠ b → st[b, d][a] = st[a];%In-insert: ⊦ a ∈ st[b, d] ↔ a = b ∨ a ∈ st;%subset-elem-eq-02: ⊦ b ∈ st ∧ st ⊆ st1 → (st[b] = st1[b] ↔ true); Used formulas: a2 = a