| # st0 < # st1, a ∈ st1, a ∈ st0, st1 -- a ⊆ st0 -- a, ∀ st. ¬ # st < # st1 ∨ ¬ st1 ⊆ st ⊦ st1[a, st0[a]] = ∅, st1[a] = st0[a], st1 = ∅, st1 ⊆ st0[a, st1[a]] |
⊦ st ⊆ st0[a, d] ↔ st ⊆ st0 ∧ ¬ a ∈ st ∨ a ∈ st ∧ st[a] = d ∧ st -- a ⊆ st0 -- a
Used terms: st1[a], a, st0, st1