| unchanged(str0, r, st, st1), level⊆(str, str0), junkrefs(str, r ' + refs0, st[r -- _type] .type, st) ⊦ ∃ refs. refs ≠ [] ∧ refs .first = r ∧ junkrefs(str, refs, st1[refs .first -- _type] .type, st1) |
unchanged(str0, r, st, st1), level⊆(str, str0), junkrefs(str, r ' + refs0, st[r -- _type] .type, st) ⊦ r ' + refs0 ≠ [] ∧ (r ' + refs0) .first = r ∧ junkrefs(str, r ' + refs0, st1[(r ' + refs0) .first -- _type] .type, st1)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (r ' + refs0)]]