| Step |
Hyp |
Ref |
Expression |
| 1 |
|
idn1 |
|- (. ( a C_ On /\ a =/= (/) ) ->. ( a C_ On /\ a =/= (/) ) ). |
| 2 |
|
simpr |
|- ( ( a C_ On /\ a =/= (/) ) -> a =/= (/) ) |
| 3 |
1 2
|
e1a |
|- (. ( a C_ On /\ a =/= (/) ) ->. a =/= (/) ). |
| 4 |
|
exmid |
|- ( ( a i^i x ) = (/) \/ -. ( a i^i x ) = (/) ) |
| 5 |
|
onfrALTlem1VD |
|- (. ( a C_ On /\ a =/= (/) ) ,. ( x e. a /\ ( a i^i x ) = (/) ) ->. E. y e. a ( a i^i y ) = (/) ). |
| 6 |
5
|
in2an |
|- (. ( a C_ On /\ a =/= (/) ) ,. x e. a ->. ( ( a i^i x ) = (/) -> E. y e. a ( a i^i y ) = (/) ) ). |
| 7 |
|
onfrALTlem2VD |
|- (. ( a C_ On /\ a =/= (/) ) ,. ( x e. a /\ -. ( a i^i x ) = (/) ) ->. E. y e. a ( a i^i y ) = (/) ). |
| 8 |
7
|
in2an |
|- (. ( a C_ On /\ a =/= (/) ) ,. x e. a ->. ( -. ( a i^i x ) = (/) -> E. y e. a ( a i^i y ) = (/) ) ). |
| 9 |
|
pm2.61 |
|- ( ( ( a i^i x ) = (/) -> E. y e. a ( a i^i y ) = (/) ) -> ( ( -. ( a i^i x ) = (/) -> E. y e. a ( a i^i y ) = (/) ) -> E. y e. a ( a i^i y ) = (/) ) ) |
| 10 |
9
|
a1i |
|- ( ( ( a i^i x ) = (/) \/ -. ( a i^i x ) = (/) ) -> ( ( ( a i^i x ) = (/) -> E. y e. a ( a i^i y ) = (/) ) -> ( ( -. ( a i^i x ) = (/) -> E. y e. a ( a i^i y ) = (/) ) -> E. y e. a ( a i^i y ) = (/) ) ) ) |
| 11 |
4 6 8 10
|
e022 |
|- (. ( a C_ On /\ a =/= (/) ) ,. x e. a ->. E. y e. a ( a i^i y ) = (/) ). |
| 12 |
11
|
in2 |
|- (. ( a C_ On /\ a =/= (/) ) ->. ( x e. a -> E. y e. a ( a i^i y ) = (/) ) ). |
| 13 |
12
|
gen11 |
|- (. ( a C_ On /\ a =/= (/) ) ->. A. x ( x e. a -> E. y e. a ( a i^i y ) = (/) ) ). |
| 14 |
|
19.23v |
|- ( A. x ( x e. a -> E. y e. a ( a i^i y ) = (/) ) <-> ( E. x x e. a -> E. y e. a ( a i^i y ) = (/) ) ) |
| 15 |
14
|
biimpi |
|- ( A. x ( x e. a -> E. y e. a ( a i^i y ) = (/) ) -> ( E. x x e. a -> E. y e. a ( a i^i y ) = (/) ) ) |
| 16 |
13 15
|
e1a |
|- (. ( a C_ On /\ a =/= (/) ) ->. ( E. x x e. a -> E. y e. a ( a i^i y ) = (/) ) ). |
| 17 |
|
n0 |
|- ( a =/= (/) <-> E. x x e. a ) |
| 18 |
|
imbi1 |
|- ( ( a =/= (/) <-> E. x x e. a ) -> ( ( a =/= (/) -> E. y e. a ( a i^i y ) = (/) ) <-> ( E. x x e. a -> E. y e. a ( a i^i y ) = (/) ) ) ) |
| 19 |
18
|
biimprcd |
|- ( ( E. x x e. a -> E. y e. a ( a i^i y ) = (/) ) -> ( ( a =/= (/) <-> E. x x e. a ) -> ( a =/= (/) -> E. y e. a ( a i^i y ) = (/) ) ) ) |
| 20 |
16 17 19
|
e10 |
|- (. ( a C_ On /\ a =/= (/) ) ->. ( a =/= (/) -> E. y e. a ( a i^i y ) = (/) ) ). |
| 21 |
|
pm2.27 |
|- ( a =/= (/) -> ( ( a =/= (/) -> E. y e. a ( a i^i y ) = (/) ) -> E. y e. a ( a i^i y ) = (/) ) ) |
| 22 |
3 20 21
|
e11 |
|- (. ( a C_ On /\ a =/= (/) ) ->. E. y e. a ( a i^i y ) = (/) ). |
| 23 |
22
|
in1 |
|- ( ( a C_ On /\ a =/= (/) ) -> E. y e. a ( a i^i y ) = (/) ) |
| 24 |
23
|
ax-gen |
|- A. a ( ( a C_ On /\ a =/= (/) ) -> E. y e. a ( a i^i y ) = (/) ) |
| 25 |
|
dfepfr |
|- ( _E Fr On <-> A. a ( ( a C_ On /\ a =/= (/) ) -> E. y e. a ( a i^i y ) = (/) ) ) |
| 26 |
25
|
biimpri |
|- ( A. a ( ( a C_ On /\ a =/= (/) ) -> E. y e. a ( a i^i y ) = (/) ) -> _E Fr On ) |
| 27 |
24 26
|
e0a |
|- _E Fr On |