theorem zsndeqd (_G: wff) (_n1 _n2: nat): $ _G -> _n1 = _n2 $ > $ _G -> zsnd _n1 = zsnd _n2 $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hyp _nh | _G -> _n1 = _n2 |
|
| 2 | 1 | appeq2d | _G -> case (\ mpos, 0) (\ mneg, suc mneg) @ _n1 = case (\ mpos, 0) (\ mneg, suc mneg) @ _n2 |
| 3 | 2 | conv zsnd | _G -> zsnd _n1 = zsnd _n2 |