⊦ ns = ns0 ↔ (∀ ino. ino ∈ ns ↔ ino ∈ ns0)
Used simplifier rules: abs-keys: ⊦ n ∈ abs-keys(ks) ↔ inodekey(n) ∈ ks;% ⊦ ¬ key ∈ ∅; (s)% ⊦ ¬ ino ∈ ∅; (s) Used terms: ∅, abs-keys(∅)