| ∀ a. a ∈ st0 → (∃ st1. ¬ a ∈ st1 ∧ st0 = st1[a, st0[a]]), a ∈ st0[a0, d] ⊦ ∃ st1. ¬ a ∈ st1 ∧ st0[a0, d] = st1[a, st0[a0, d][a]] |
⊦ a ∈ st[b, d] ↔ a = b ∨ a ∈ st
∀ a. a ∈ st0 → (∃ st1. ¬ a ∈ st1 ∧ st0 = st1[a, st0[a]]), a = a0 ∨ a ∈ st0 ⊦ ∃ st1. ¬ a ∈ st1 ∧ st0[a0, d] = st1[a, st0[a0, d][a]]
Used terms: d, a0, st0, a