| validval(str, rk, val, st), validvals(str, rkvs, st), rkv ∈ rkvs ⊦ validval(str, rkv .1, rkv .2, st[rk, val]) |
rkv = rk0 × val0, validval(str, rk, val, st), validvals(str, rkvs, st), rkv ∈ rkvs ⊦ validval(str, rk0, val0, st[rk, val])
[[CONCRETESIMPRULES : ([CSIMPELIM : ⊦ rk = rkv .1 ∧ val = rkv .2 ↔ rkv = rk × val])], [EXTRATERMS : (rkv, rk0, val0)]]