| st1 -- (r0 -- sk) = update(r0, fis, st0 -- (r0 -- sk)), # st0 = m + 1, st1 = (update(r0, fis, st0)[r0 -- sk, st1[r0 -- sk]]), sk ∈ fis, validFields(r0, fis, st0), unique_al(fis), r0 ∈ st0, r0 ∈ st1, r0 -- sk ∈ st0, r0 -- sk ∈ st1, r0 -- _length ∈ st0 → st0[r0 -- _length] = st1[r0 -- _length], r0 -- _type ∈ st0 → st0[r0 -- _type] = st1[r0 -- _type], ∀ r1, sk. r1 ≠ r0 → st0[r1 -- sk] = st1[r1 -- sk], ∀ rk. rk ∈ st0 ↔ rk ∈ st1, ∀ sk0. sk0 ∈ fis .keys → r0 -- sk0 ∈ st0 ⊦ st0 = ∅, st0[r0 -- sk] = st1[r0 -- sk], _type ∈ fis, _length ∈ fis, sk ∈ fis .keys |
⊦ sk ∈ fis .keys ↔ sk ∈ fis
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (fis, sk)]]