| ⊦ (ri ⊖ ro) -- key = (ri -- key) ⊖ ro, key ∈ ro |
⊦ ri = ri0 ↔ (∀ key. (key ∈ ri ↔ key ∈ ri0) ∧ (key ∈ ri → ri[key] = ri0[key]))
⊦ key ∈ ro, ∀ key0. (key0 ∈ (ri ⊖ ro) -- key ↔ key0 ∈ (ri -- key) ⊖ ro) ∧ (key0 ∈ (ri ⊖ ro) -- key → ((ri ⊖ ro) -- key)[key0] = ((ri -- key) ⊖ ro)[key0])
Used terms: (ri -- key) ⊖ ro, (ri ⊖ ro) -- key