| sk = fs ', fs = mkfs(class, ty0, fieldvar), is_fskey(sk), ∀ str, r, ty, class, st. validref(str, r, ty, addclass(class, fis0, st)) ↔ validref(str, r, ty, st) ⊦ validref(str, r, ty, addclass(class, (sk × val) ' + 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, (mkfs(class, ty0, fieldvar) ' × val) ' + fis0, st)) ↔ validref(str, r, ty, st)
[[CONCRETESIMPRULES : ([CSIMPSEQ : ⊦ is_fskey(fs ')])]]