| adr0 ∈ ri \ datakeys(key, ino, ri) ⊦ adr0 = adr, adr0 ∈ ri |
⊦ adr ∈ ri ↔ (∃ key. key ∈ ri ∧ ri[key] = adr)
∃ key0. key0 ∈ ri \ datakeys(key, ino, ri) ∧ (ri \ datakeys(key, ino, ri))[key0] = adr0 ⊦ adr0 = adr, adr0 ∈ ri
Used terms: ri \ datakeys(key, ino, ri), adr0