| Step |
Hyp |
Ref |
Expression |
| 1 |
|
neq0 |
|- ( -. x = (/) <-> E. y y e. x ) |
| 2 |
|
indistop |
|- { (/) , A } e. Top |
| 3 |
|
indistop |
|- { (/) , B } e. Top |
| 4 |
|
eltx |
|- ( ( { (/) , A } e. Top /\ { (/) , B } e. Top ) -> ( x e. ( { (/) , A } tX { (/) , B } ) <-> A. y e. x E. z e. { (/) , A } E. w e. { (/) , B } ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) ) |
| 5 |
2 3 4
|
mp2an |
|- ( x e. ( { (/) , A } tX { (/) , B } ) <-> A. y e. x E. z e. { (/) , A } E. w e. { (/) , B } ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) |
| 6 |
|
rsp |
|- ( A. y e. x E. z e. { (/) , A } E. w e. { (/) , B } ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) -> ( y e. x -> E. z e. { (/) , A } E. w e. { (/) , B } ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) ) |
| 7 |
5 6
|
sylbi |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> ( y e. x -> E. z e. { (/) , A } E. w e. { (/) , B } ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) ) |
| 8 |
|
elssuni |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> x C_ U. ( { (/) , A } tX { (/) , B } ) ) |
| 9 |
|
indisuni |
|- ( _I ` A ) = U. { (/) , A } |
| 10 |
|
indisuni |
|- ( _I ` B ) = U. { (/) , B } |
| 11 |
2 3 9 10
|
txunii |
|- ( ( _I ` A ) X. ( _I ` B ) ) = U. ( { (/) , A } tX { (/) , B } ) |
| 12 |
8 11
|
sseqtrrdi |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> x C_ ( ( _I ` A ) X. ( _I ` B ) ) ) |
| 13 |
12
|
ad2antrr |
|- ( ( ( x e. ( { (/) , A } tX { (/) , B } ) /\ ( z e. { (/) , A } /\ w e. { (/) , B } ) ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> x C_ ( ( _I ` A ) X. ( _I ` B ) ) ) |
| 14 |
|
ne0i |
|- ( y e. ( z X. w ) -> ( z X. w ) =/= (/) ) |
| 15 |
14
|
ad2antrl |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( z X. w ) =/= (/) ) |
| 16 |
|
xpnz |
|- ( ( z =/= (/) /\ w =/= (/) ) <-> ( z X. w ) =/= (/) ) |
| 17 |
15 16
|
sylibr |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( z =/= (/) /\ w =/= (/) ) ) |
| 18 |
17
|
simpld |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> z =/= (/) ) |
| 19 |
18
|
neneqd |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> -. z = (/) ) |
| 20 |
|
simpll |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> z e. { (/) , A } ) |
| 21 |
|
indislem |
|- { (/) , ( _I ` A ) } = { (/) , A } |
| 22 |
20 21
|
eleqtrrdi |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> z e. { (/) , ( _I ` A ) } ) |
| 23 |
|
elpri |
|- ( z e. { (/) , ( _I ` A ) } -> ( z = (/) \/ z = ( _I ` A ) ) ) |
| 24 |
22 23
|
syl |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( z = (/) \/ z = ( _I ` A ) ) ) |
| 25 |
24
|
ord |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( -. z = (/) -> z = ( _I ` A ) ) ) |
| 26 |
19 25
|
mpd |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> z = ( _I ` A ) ) |
| 27 |
17
|
simprd |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> w =/= (/) ) |
| 28 |
27
|
neneqd |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> -. w = (/) ) |
| 29 |
|
simplr |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> w e. { (/) , B } ) |
| 30 |
|
indislem |
|- { (/) , ( _I ` B ) } = { (/) , B } |
| 31 |
29 30
|
eleqtrrdi |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> w e. { (/) , ( _I ` B ) } ) |
| 32 |
|
elpri |
|- ( w e. { (/) , ( _I ` B ) } -> ( w = (/) \/ w = ( _I ` B ) ) ) |
| 33 |
31 32
|
syl |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( w = (/) \/ w = ( _I ` B ) ) ) |
| 34 |
33
|
ord |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( -. w = (/) -> w = ( _I ` B ) ) ) |
| 35 |
28 34
|
mpd |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> w = ( _I ` B ) ) |
| 36 |
26 35
|
xpeq12d |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( z X. w ) = ( ( _I ` A ) X. ( _I ` B ) ) ) |
| 37 |
|
simprr |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( z X. w ) C_ x ) |
| 38 |
36 37
|
eqsstrrd |
|- ( ( ( z e. { (/) , A } /\ w e. { (/) , B } ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( ( _I ` A ) X. ( _I ` B ) ) C_ x ) |
| 39 |
38
|
adantll |
|- ( ( ( x e. ( { (/) , A } tX { (/) , B } ) /\ ( z e. { (/) , A } /\ w e. { (/) , B } ) ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> ( ( _I ` A ) X. ( _I ` B ) ) C_ x ) |
| 40 |
13 39
|
eqssd |
|- ( ( ( x e. ( { (/) , A } tX { (/) , B } ) /\ ( z e. { (/) , A } /\ w e. { (/) , B } ) ) /\ ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) ) -> x = ( ( _I ` A ) X. ( _I ` B ) ) ) |
| 41 |
40
|
ex |
|- ( ( x e. ( { (/) , A } tX { (/) , B } ) /\ ( z e. { (/) , A } /\ w e. { (/) , B } ) ) -> ( ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) -> x = ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 42 |
41
|
rexlimdvva |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> ( E. z e. { (/) , A } E. w e. { (/) , B } ( y e. ( z X. w ) /\ ( z X. w ) C_ x ) -> x = ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 43 |
7 42
|
syld |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> ( y e. x -> x = ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 44 |
43
|
exlimdv |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> ( E. y y e. x -> x = ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 45 |
1 44
|
biimtrid |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> ( -. x = (/) -> x = ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 46 |
45
|
orrd |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> ( x = (/) \/ x = ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 47 |
|
vex |
|- x e. _V |
| 48 |
47
|
elpr |
|- ( x e. { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } <-> ( x = (/) \/ x = ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 49 |
46 48
|
sylibr |
|- ( x e. ( { (/) , A } tX { (/) , B } ) -> x e. { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } ) |
| 50 |
49
|
ssriv |
|- ( { (/) , A } tX { (/) , B } ) C_ { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } |
| 51 |
9
|
toptopon |
|- ( { (/) , A } e. Top <-> { (/) , A } e. ( TopOn ` ( _I ` A ) ) ) |
| 52 |
2 51
|
mpbi |
|- { (/) , A } e. ( TopOn ` ( _I ` A ) ) |
| 53 |
10
|
toptopon |
|- ( { (/) , B } e. Top <-> { (/) , B } e. ( TopOn ` ( _I ` B ) ) ) |
| 54 |
3 53
|
mpbi |
|- { (/) , B } e. ( TopOn ` ( _I ` B ) ) |
| 55 |
|
txtopon |
|- ( ( { (/) , A } e. ( TopOn ` ( _I ` A ) ) /\ { (/) , B } e. ( TopOn ` ( _I ` B ) ) ) -> ( { (/) , A } tX { (/) , B } ) e. ( TopOn ` ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 56 |
52 54 55
|
mp2an |
|- ( { (/) , A } tX { (/) , B } ) e. ( TopOn ` ( ( _I ` A ) X. ( _I ` B ) ) ) |
| 57 |
|
topgele |
|- ( ( { (/) , A } tX { (/) , B } ) e. ( TopOn ` ( ( _I ` A ) X. ( _I ` B ) ) ) -> ( { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } C_ ( { (/) , A } tX { (/) , B } ) /\ ( { (/) , A } tX { (/) , B } ) C_ ~P ( ( _I ` A ) X. ( _I ` B ) ) ) ) |
| 58 |
56 57
|
ax-mp |
|- ( { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } C_ ( { (/) , A } tX { (/) , B } ) /\ ( { (/) , A } tX { (/) , B } ) C_ ~P ( ( _I ` A ) X. ( _I ` B ) ) ) |
| 59 |
58
|
simpli |
|- { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } C_ ( { (/) , A } tX { (/) , B } ) |
| 60 |
50 59
|
eqssi |
|- ( { (/) , A } tX { (/) , B } ) = { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } |
| 61 |
|
txindislem |
|- ( ( _I ` A ) X. ( _I ` B ) ) = ( _I ` ( A X. B ) ) |
| 62 |
61
|
preq2i |
|- { (/) , ( ( _I ` A ) X. ( _I ` B ) ) } = { (/) , ( _I ` ( A X. B ) ) } |
| 63 |
|
indislem |
|- { (/) , ( _I ` ( A X. B ) ) } = { (/) , ( A X. B ) } |
| 64 |
60 62 63
|
3eqtri |
|- ( { (/) , A } tX { (/) , B } ) = { (/) , ( A X. B ) } |