| st0 .refs ∩ st .refs = ∅, validref(str, r, ty, st0) ⊦ validref(str, r, ty, st0 ∪ st) |
⊦ validref(str, r, ty, st) ∧ st ⊆ st1 → validref(str, r, ty, st1)
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ (rset ∩ rset0) ∩ rset1 = rset ∩ rset0 ∩ rset1], [CSIMPSEQ : ⊦ rset ∩ rset0 = rset0 ∩ rset], [CSIMPSEQ : ⊦ st .refs ∩ st0 .refs = ∅ → st ⊆ st ∪ st0])], [EXTRATERMS : (str, r, ty, st0, st0 ∪ st)]]