| level⊆(str, str0), junkref(str, r, st), unchanged(str0, r, st, st1) ⊦ junkref(str, r, st1) |
⊦ junkref(str, r, st) ↔ (∃ refs. refs ≠ [] ∧ refs .first = r ∧ junkrefs(str, refs, st[r -- _type] .type, st))
level⊆(str, str0), ∃ refs. refs ≠ [] ∧ refs .first = r ∧ junkrefs(str, refs, st[r -- _type] .type, st), unchanged(str0, r, st, st1) ⊦ junkref(str, r, st1)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st, r, str)]]