| Step |
Hyp |
Ref |
Expression |
| 1 |
|
slenlt |
|- ( ( A e. No /\ B e. No ) -> ( A <_s B <-> -. B |
| 2 |
|
orcom |
|- ( ( A ( A = B \/ A |
| 3 |
|
eqcom |
|- ( A = B <-> B = A ) |
| 4 |
3
|
orbi1i |
|- ( ( A = B \/ A ( B = A \/ A |
| 5 |
2 4
|
bitri |
|- ( ( A ( B = A \/ A |
| 6 |
|
sltso |
|- |
| 7 |
|
sotric |
|- ( ( ( B -. ( B = A \/ A |
| 8 |
6 7
|
mpan |
|- ( ( B e. No /\ A e. No ) -> ( B -. ( B = A \/ A |
| 9 |
8
|
ancoms |
|- ( ( A e. No /\ B e. No ) -> ( B -. ( B = A \/ A |
| 10 |
9
|
con2bid |
|- ( ( A e. No /\ B e. No ) -> ( ( B = A \/ A -. B |
| 11 |
5 10
|
bitrid |
|- ( ( A e. No /\ B e. No ) -> ( ( A -. B |
| 12 |
1 11
|
bitr4d |
|- ( ( A e. No /\ B e. No ) -> ( A <_s B <-> ( A |