| a ∈ st0, a0 ∈ st[a, st0[a]], ∀ a0. a0 ∈ st -- a → a0 ∈ st0 ∧ (st -- a)[a0] = st0[a0] ⊦ a0 = a, a0 ∈ st0 ∧ st[a, st0[a]][a0] = st0[a0] |
a ∈ st0, a0 ∈ st, ∀ a1. a1 ∈ st -- a → a1 ∈ st0 ∧ st[a1] = st0[a1] ⊦ a0 = a, a0 ∈ st0 ∧ st[a0] = st0[a0]
Used simplifier rules: in-neq: ⊦ a ≠ b → (a ∈ st[b, d] ↔ a ∈ st);%Del-in: ⊦ a ∈ st -- b ↔ a ≠ b ∧ a ∈ st;%Del-at-strong: a ≠ b ⊦ (st -- b)[a] = st[a];%At-other: ⊦ a ≠ b → st[b, d][a] = st[a];