| 1. |
| Premise |
|
1 |
|
(^x)Ax |
| 1 ^E |
|
2 |
|
Aa |
| 1 ^E |
|
3 |
|
Ab |
| 2,3 &I |
|
4 |
|
Aa&Ab |
|
| 3. |
| Assumption |
|
1 |
|
....what if |
(^x)(Tx&~Ux) |
| 1 ^E |
|
2 |
|
....then... |
Ta&~Ua |
| 2 &E |
|
3 |
|
....then... |
Ta |
| 3 %I |
|
4 |
|
....then... |
(%y)Ty |
| 1-4 >I |
|
5 |
|
(^x)(Tx&~Ux)>(%y)Ty |
|
|
| 5. |
| Premise |
|
1 |
|
(^y)(Ty>Uy) |
| Premise |
|
2 |
|
Ta |
| 1 ^E |
|
3 |
|
Ta>Ua |
| 2,3 >E |
|
4 |
|
Ua |
| 2,4 &I |
|
5 |
|
Ua&Ta |
| 5 %I |
|
6 |
|
(%z)(Uz&Tz) |
|