theorem pi22eqd (_G: wff) (_n1 _n2: nat): $ _G -> _n1 = _n2 $ > $ _G -> pi22 _n1 = pi22 _n2 $;
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | hyp _nh | _G -> _n1 = _n2 |
|
2 | 1 | sndeqd | _G -> snd _n1 = snd _n2 |
3 | 2 | sndeqd | _G -> snd (snd _n1) = snd (snd _n2) |
4 | 3 | conv pi22 | _G -> pi22 _n1 = pi22 _n2 |