| ∀ st0, r1, sk1, val0, r2. (st0[r1 -- sk1, val0][r2 -- sks0]) ≠ st0[r2 -- sks0] → (∃ sks, sks1. sks0 = sks + sk1 ' + sks1 ∧ st0[r2 -- sks] .refval = r1), r ≠ r0 ∨ sk0 ≠ sk ⊦ sks0 = [], (st[r0 -- sk, val][st[r -- sk0] .refval -- sks0]) = st[r -- (sk0 ' + sks0)], ∃ sks, sks1. sk0 ' + sks0 = sks + sk ' + sks1 ∧ st[r -- sks] .refval = r0 |
⊦ sks ≠ [] → st[r -- (sk ' + sks)] = st[st[r -- sk] .refval -- sks]
sks0 ≠ [], ∀ st0, r1, sk1, val0, r2. (st0[r1 -- sk1, val0][r2 -- sks0]) ≠ st0[r2 -- sks0] → (∃ sks, sks1. sks0 = sks + sk1 ' + sks1 ∧ st0[r2 -- sks] .refval = r1), r ≠ r0 ∨ sk0 ≠ sk ⊦ sks0 = [], (st[r0 -- sk, val][st[r -- sk0] .refval -- sks0]) = st[st[r -- sk0] .refval -- sks0], ∃ sks, sks1. sk0 ' + sks0 = sks + sk ' + sks1 ∧ st[r -- sks] .refval = r0
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (sks0, sk0, r, st)]]