| ∃ refs. refs ≠ [] ∧ refs .first = r ∧ refs .last = r1 ∧ validrefs(str, refs, (st[r0 -- sk, val][r -- _type]) .type, st[r0 -- sk, val]) ⊦ path∃(str, r, r1, st), sk = _type, path∃(str, r, r0, st), junkref(str, r, st) |
validrefs(str, refs, st[refs .first -- _type] .type, st[r0 -- sk, val]) ⊦ sk = _type, refs = [], path∃(str, refs .first, refs .last, st), path∃(str, refs .first, r0, st), junkref(str, refs .first, st)
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ sk ≠ sk0 → (st[r -- sk, val][r0 -- sk0]) = st[r0 -- sk0]])]]