theorem trueeqd (_G: wff) (_n1 _n2: nat): $ _G -> _n1 = _n2 $ > $ _G -> (true _n1 <-> true _n2) $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | hyp _nh | _G -> _n1 = _n2 |
|
| 2 | 1 | neeq1d | _G -> (_n1 != 0 <-> _n2 != 0) |
| 3 | 2 | conv true | _G -> (true _n1 <-> true _n2) |