⊦ ¬ junkref(str, r, st) ∧ st ⊆ st1 → ¬ junkref(str, r, st1)
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ st0 ⊆ st ∪ st0])], [EXTRATERMS : (str, r, st, st0 ∪ st)]]