| ⊦ rkvs = [], st[rkvs] = (st[rkvs .butlast][rkvs .last .1, rkvs .last .2]) |
rkvs .last = rk × val ⊦ rkvs = [], st[rkvs] = (st[rkvs .butlast][rk, val])
[[CONCRETESIMPRULES : ([CSIMPELIM : ⊦ rk = rkv .1 ∧ val = rkv .2 ↔ rkv = rk × val])], [EXTRATERMS : (rkvs .last, rk, val)]]