| st1[r -- sk, val] ⊆ st0, # st0 .refs ≤ # st1 .refs, ∀ st. # st1 .refs ≤ # st .refs ∨ ¬ st1 ⊆ st ⊦ r ∈ st1 .refs |
⊦ st[rk, val] ⊆ st0 ↔ st -- rk ⊆ st0 -- rk ∧ rk × val ∈ st0
st1 -- (r -- sk) ⊆ st0 -- (r -- sk) ∧ (r -- sk) × val ∈ st0, # st0 .refs ≤ # st1 .refs, ∀ st. # st1 .refs ≤ # st .refs ∨ ¬ st1 ⊆ st ⊦ r ∈ st1 .refs
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st0, val, r -- sk, st1)]]