| ¬ junkref(str, r, st), ¬ cyclic(str, r, st) ⊦ ∃ refs. validrefs(str, refs, st[r -- _type] .type, st) ∧ refs ≠ [] ∧ ¬ dups(refs) ∧ refs .first = r ∧ ¬ has_reffield(refs .last, st) |
⊦ cyclic(str, r, st), junkref(str, r, st), ∃ refs. validrefs(str, refs, st[refs .first -- _type] .type, st) ∧ refs ≠ [] ∧ ¬ dups(refs) ∧ refs .first = r ∧ ¬ has_reffield(refs .last, st)
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