| ¬ (is_fskey(fv .1) ∧ fv .1 .fs .class ≠ class), ∀ str, r, ty, class, st. validref(str, r, ty, addclass(class, fis0, st)) ↔ validref(str, r, ty, st) ⊦ validref(str, r, ty, addclass(class, fv ' + fis0, st)) ↔ validref(str, r, ty, st) |
∀ str, r, ty, class, st. validref(str, r, ty, addclass(class, fis0, st)) ↔ validref(str, r, ty, st) ⊦ validref(str, r, ty, addclass(class, fv ' + fis0, st)) ↔ validref(str, r, ty, st), ¬ is_indexkey(fv .1) ∧ fv .1 .fs .class ≠ class
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ ¬ is_fskey(sk) ↔ is_indexkey(sk)])]]