| validrefkeynotnull(str, r -- fs ', ty, st1) ⊦ st1[r -- fs '] = (st ∪ st1)[r -- fs '] |
⊦ validrefkeynotnull(str, rk, ty, st) ↔ rk ∈ st ∧ validrefvalnotnull(str, st[rk], ty, st)
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ rk ∈ st0 → (st ∪ st0)[rk] = st0[rk]])], [EXTRATERMS : (st1, ty, r -- fs ', str)]]