| ⊦ key ∈ ro, ∀ key0. (key0 ∈ (ri ⊖ ro) \ datakeys(key, n, ri) ↔ key0 ∈ (ri \ datakeys(key, n, ri)) ⊖ ro) ∧ (key0 ∈ (ri ⊖ ro) \ datakeys(key, n, ri) → ((ri ⊖ ro) \ datakeys(key, n, ri))[key0] = ((ri \ datakeys(key, n, ri)) ⊖ ro)[key0]) |
⊦ key ∈ ro, (key0 ∈ (ri ⊖ ro) \ datakeys(key, n, ri) ↔ key0 ∈ (ri \ datakeys(key, n, ri)) ⊖ ro) ∧ (key0 ∈ (ri ⊖ ro) \ datakeys(key, n, ri) → ((ri ⊖ ro) \ datakeys(key, n, ri))[key0] = ((ri \ datakeys(key, n, ri)) ⊖ ro)[key0])