| key ∈ ri, ∀ key0, key1. key0 ∈ ri ∧ key1 ∈ ri ∧ ri[key0] = ri[key1] → key0 = key1, ∃ key. key ∈ ri ∧ ri[key] = adr ⊦ adr = ri[key], ∃ key0. key0 ≠ key ∧ key0 ∈ ri ∧ ri[key0] = adr |
key0 ∈ ri, key ∈ ri, ∀ key0, key1. key0 ∈ ri ∧ key1 ∈ ri ∧ ri[key0] = ri[key1] → key0 = key1 ⊦ ri[key0] = ri[key], ∃ key1. key1 ∈ ri ∧ ri[key1] = ri[key0]