| validref(str, r, ty, st), path∃(str0, r, r0, st), level⊆(str, str0) ⊦ path∃(str, r, r0, st) |
⊦ r ≠ r0 → (path∃(str, r, r0, st) ↔ (∃ refs. refs ≠ [] ∧ refs .first = r ∧ refs .last = r0 ∧ ¬ dups(refs) ∧ validrefs(str, refs, st[r -- _type] .type, st)))
¬ r ≠ r0, validref(str, r, ty, st), path∃(str0, r, r0, st), level⊆(str, str0) ⊦ path∃(str, r, r0, st)
r ≠ r0, validref(str, r, ty, st), ∃ refs. refs ≠ [] ∧ refs .first = r ∧ refs .last = r0 ∧ ¬ dups(refs) ∧ validrefs(str0, refs, st[r -- _type] .type, st), level⊆(str, str0) ⊦ path∃(str, r, r0, st)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st, r0, r, str0)]]