| ⊦ ∀ key0. key0 ∈ datakeys(ks ++ key, ri) ↔ key0 ∈ datakeys(ks, ri) ∪ datakeys(key, ri) |
⊦ key0 ∈ ri ∧ key0.data? ∧ (inodekey(key0.ino) = key ∨ inodekey(key0.ino) ∈ ks) ↔ key0 ∈ datakeys(ks, ri) ∪ datakeys(key, ri)
Used simplifier rules: datakeys-set: ⊦ key ∈ datakeys(ks, ri) ↔ key ∈ ri ∧ key.data? ∧ inodekey(key.ino) ∈ ks;% ⊦ key ∈ ks ++ key0 ↔ key = key0 ∨ key ∈ ks; (s)