| st1 .refs ∩ st .refs = ∅, r ∈ st, junkrefs(str, r ' + refs0, st[r -- _type] .type, st1 ∪ st), r ∈ st1, r -- _type ∈ st, r ∈ st .refs ⊦ st = ∅, junkrefs(str, r ' + refs0, st1[r -- _type] .type, st1), ∃ refs. refs ≠ [] ∧ refs .first = r ∧ junkrefs(str, refs, st1[refs .first -- _type] .type, st1) |
⊦ r ∈ st ↔ r ∈ st .refs
st1 .refs ∩ st .refs = ∅, r ∈ st .refs, junkrefs(str, r ' + refs0, st[r -- _type] .type, st1 ∪ st), r ∈ st1, r -- _type ∈ st, r ∈ st .refs ⊦ st = ∅, junkrefs(str, r ' + refs0, st1[r -- _type] .type, st1), ∃ refs. refs ≠ [] ∧ refs .first = r ∧ junkrefs(str, refs, st1[refs .first -- _type] .type, st1)
[[CONCRETESIMPRULES : ()], [EXTRATERMS : (st, r)]]