| validrefs(str, r ' + refs0, st[r -- _type] .type, st[(r ' + refs0) .last -- sk, val]) ⊦ sk = _type, r = (r ' + refs0) .last, path∃(str, r, (r ' + refs0) .last, st), junkref(str, r, st), dups(refs0), r ∈ refs0 |
r ' + refs0 = refs + r0 ' ∧ r ' + refs0 ≠ [], validrefs(str, r ' + refs0, st[r -- _type] .type, st[r0 -- sk, val]) ⊦ sk = _type, r = r0, path∃(str, r, r0, st), junkref(str, r, st), dups(refs0), r ∈ refs0
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ ¬ refs + refs0 ≠ [] ↔ refs = [] ∧ refs0 = []], [CSIMPSEQ : ⊦ r ' ≠ []], [CSIMPSEQ : ⊦ (refs + refs0) + refs1 = refs + refs0 + refs1], [CSIMPELIM : refs ≠ [] ⊦ r = refs .last ∧ refs0 = refs .butlast ↔ refs = refs0 + r '])], [EXTRATERMS : (r ' + refs0, r0, refs)]]