| validrefs(str, refs, ty, st), ∀ st, ty, str, refs0. # refs0 < # refs → ( validrefs(str, refs0, ty, st) ∧ refs0 ≠ [] → (∃ refs1. validrefs(str, refs1, ty, st) ∧ refs1 ≠ [] ∧ refs1 .last = refs0 .last ∧ refs0 .first = refs1 .first ∧ ¬ dups(refs1))) ⊦ refs = [], validrefs(str, refs, ty, st) ∧ refs ≠ [] ∧ refs .last = refs .last ∧ refs .first = refs .first ∧ ¬ dups(refs), ∃ refs0. validrefs(str, refs0, ty, st) ∧ refs0 ≠ [] ∧ refs0 .last = refs .last ∧ refs .first = refs0 .first ∧ ¬ dups(refs0) |
validrefs(str, refs, ty, st), dups(refs), ∀ st, ty, str, refs0. # refs0 < # refs → ( validrefs(str, refs0, ty, st) ∧ refs0 ≠ [] → (∃ refs1. validrefs(str, refs1, ty, st) ∧ refs1 ≠ [] ∧ refs1 .last = refs0 .last ∧ refs0 .first = refs1 .first ∧ ¬ dups(refs1))) ⊦ refs = [], ∃ refs0. validrefs(str, refs0, ty, st) ∧ refs0 ≠ [] ∧ refs0 .last = refs .last ∧ refs .first = refs0 .first ∧ ¬ dups(refs0)
[[CONCRETESIMPRULES : ()]]