| junkrefs(str, r1 ' + acc, ty, st[r0 -- sk, val]), is_valid_ref(str, r0, st), ∀ str0, r2, st0, sk0, ty0, val0. ¬ path∃(str0, acc .first, r2, st0) ∧ is_valid_ref(str0, r2, st0) ∧ sk0 ≠ _type ∧ acc ≠ [] → (junkrefs(str0, acc, ty0, st0[r2 -- sk0, val0]) ↔ junkrefs(str0, acc, ty0, st0)) ⊦ junkrefs(str, r1 ' + acc, ty, st), sk = _type, path∃(str, r1, r0, st) |
⊦ ¬ path∃(str, r, r0, st) ∧ ¬ junkrefs(str, refs, ty, st) ∧ sk ≠ _type ∧ refs ≠ [] ∧ refs .first = r → ¬ junkrefs(str, refs, ty, st[r0 -- sk, val])
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ (refs + refs0) + refs1 = refs + refs0 + refs1], [CSIMPSEQ : ⊦ ¬ refs + refs0 ≠ [] ↔ refs = [] ∧ refs0 = []], [CSIMPSEQ : ⊦ r ' ≠ []], [CSIMPSEQ : ⊦ (r ' + refs) .first = r])], [EXTRATERMS : (str, r1, r0, st, r1 ' + acc, ty, sk, val)]]