| ⊦ (∃ key. key ∈ ks ∧ key ∈ ri ∧ adr = ri[key]) ∨ (∃ key. key ∈ ri \ ks ∧ (ri \ ks)[key] = adr) ↔ adr ∈ ri |
(∃ key. key ∈ ks ∧ key ∈ ri ∧ adr = ri[key]) ∨ (∃ key. key ∈ ri \ ks ∧ (ri \ ks)[key] = adr) ⊦ adr ∈ ri
adr ∈ ri ⊦ ∃ key. key ∈ ks ∧ key ∈ ri ∧ adr = ri[key], ∃ key. key ∈ ri \ ks ∧ (ri \ ks)[key] = adr