| ¬ (validref(str, r, st[r -- _type] .type, st) ∧ st ⊆ st0), st ⊆ st0 ⊦ validrefs(str, r ' + refs, ty, st0) ↔ validrefs(str, r ' + refs, ty, st), junkref(str, r, st) |
st ⊆ st0 ⊦ validrefs(str, r ' + refs, ty, st0) ↔ validrefs(str, r ' + refs, ty, st), junkref(str, r, st), validref(str, r, st[r -- _type] .type, st)
[[CONCRETESIMPRULES : ()]]