| rkv = rk0 × val0, validval(str, rk, val, st), validvals(str, rkvs, st), rkv ∈ rkvs ⊦ validval(str, rk0, val0, st[rk, val]) |
validval(str, rk, val, st), validvals(str, rkvs, st), rk0 × val0 ∈ rkvs ⊦ validval(str, rk0, val0, st[rk, val])
[[CONCRETESIMPRULES : ()]]