| ∀ st, r, sk0. st[st[r -- sks0] .refval -- sk0] = st[r -- (sks0 + sk0 ')] ⊦ sks0 = [], st[st[st[r -- sk] .refval -- sks0] .refval -- sk0] = st[st[r -- sk] .refval -- (sks0 + sk0 ')] |
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st, st[r -- sk] .refval, sk0)]]