theorem ocaseeq2d (_G: wff) (z: nat) (_S1 _S2: set): $ _G -> _S1 == _S2 $ > $ _G -> ocase z _S1 == ocase z _S2 $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | eqidd | _G -> z = z |
|
| 2 | hyp _h | _G -> _S1 == _S2 |
|
| 3 | 1, 2 | ocaseeqd | _G -> ocase z _S1 == ocase z _S2 |