| key ∈ ks, ∀ ks0. # ks0 < # ks → true → (∃ ino. ∀ ino0. inodekey(ino0) ∈ ks0 → ino0 < ino) ⊦ # ks = 0, ∃ ino. ∀ ino0. inodekey(ino0) ∈ ks → ino0 < ino |
⊦ key ∈ ks ↔ (∃ ks0. ks = ks0 ++ key ∧ ¬ key ∈ ks0)
∃ ks0. ks = ks0 ++ key ∧ ¬ key ∈ ks0, ∀ ks0. # ks0 < # ks → true → (∃ ino. ∀ ino0. inodekey(ino0) ∈ ks0 → ino0 < ino) ⊦ # ks = 0, ∃ ino. ∀ ino0. inodekey(ino0) ∈ ks → ino0 < ino
Used terms: ks, key