theorem the01: $ the 0 = 0 $;
| Step | Hyp | Ref | Expression |
|---|---|---|---|
| 1 | absurd | ~x e. 0 -> x e. 0 -> x = 0 |
|
| 2 | el02 | ~x e. 0 |
|
| 3 | 1, 2 | ax_mp | x e. 0 -> x = 0 |
| 4 | 3 | a1i | T. -> x e. 0 -> x = 0 |
| 5 | 4 | eqthe0d | T. -> the 0 = 0 |
| 6 | 5 | trud | the 0 = 0 |