| ⊦ sk = _type, cyclic(str, r, st[r0 -- sk, val]) ↔ cyclic(str, r, st), path∃(str, r, r0, st), junkref(str, r, st) |
⊦ cyclic(str, r, st) ↔ (∃ refs, r0. ¬ dups(refs) ∧ r0 ∈ refs ∧ refs .first = r ∧ validrefs(str, refs + r0 ', st[r -- _type] .type, st))
⊦ sk = _type, (∃ refs, r1. ¬ dups(refs) ∧ r1 ∈ refs ∧ refs .first = r ∧ validrefs(str, refs + r1 ', (st[r0 -- sk, val][r -- _type]) .type, st[r0 -- sk, val])) ↔ cyclic(str, r, st), path∃(str, r, r0, st), junkref(str, r, st)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st[r0 -- sk, val], r, str)]]