| validrefs(str, refs, st[refs .first -- _type] .type, st[refs .last -- sk, val]) ⊦ sk = _type, refs = [], refs .first = refs .last, path∃(str, refs .first, refs .last, st), junkref(str, refs .first, st), dups(refs) |
refs = r + refs0, validrefs(str, refs, st[r -- _type] .type, st[refs .last -- sk, val]) ⊦ sk = _type, refs = [], r = refs .last, path∃(str, r, refs .last, st), junkref(str, r, st), dups(refs)
[[CONCRETESIMPRULES : ([CSIMPELIM : ⊦ refs ≠ [] → ( r = refs .first ∧ refs0 = refs .rest ↔ refs = r + refs0)])], [EXTRATERMS : (refs, r, refs0)]]