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