Step |
Hyp |
Ref |
Expression |
1 |
|
unfi2 |
|- ( ( A ~< _om /\ B ~< _om ) -> ( A u. B ) ~< _om ) |
2 |
|
sdomnen |
|- ( ( A u. B ) ~< _om -> -. ( A u. B ) ~~ _om ) |
3 |
1 2
|
syl |
|- ( ( A ~< _om /\ B ~< _om ) -> -. ( A u. B ) ~~ _om ) |
4 |
3
|
con2i |
|- ( ( A u. B ) ~~ _om -> -. ( A ~< _om /\ B ~< _om ) ) |
5 |
|
ianor |
|- ( -. ( A ~< _om /\ B ~< _om ) <-> ( -. A ~< _om \/ -. B ~< _om ) ) |
6 |
|
relen |
|- Rel ~~ |
7 |
6
|
brrelex1i |
|- ( ( A u. B ) ~~ _om -> ( A u. B ) e. _V ) |
8 |
|
ssun1 |
|- A C_ ( A u. B ) |
9 |
|
ssdomg |
|- ( ( A u. B ) e. _V -> ( A C_ ( A u. B ) -> A ~<_ ( A u. B ) ) ) |
10 |
7 8 9
|
mpisyl |
|- ( ( A u. B ) ~~ _om -> A ~<_ ( A u. B ) ) |
11 |
|
domentr |
|- ( ( A ~<_ ( A u. B ) /\ ( A u. B ) ~~ _om ) -> A ~<_ _om ) |
12 |
10 11
|
mpancom |
|- ( ( A u. B ) ~~ _om -> A ~<_ _om ) |
13 |
12
|
anim1i |
|- ( ( ( A u. B ) ~~ _om /\ -. A ~< _om ) -> ( A ~<_ _om /\ -. A ~< _om ) ) |
14 |
|
bren2 |
|- ( A ~~ _om <-> ( A ~<_ _om /\ -. A ~< _om ) ) |
15 |
13 14
|
sylibr |
|- ( ( ( A u. B ) ~~ _om /\ -. A ~< _om ) -> A ~~ _om ) |
16 |
15
|
ex |
|- ( ( A u. B ) ~~ _om -> ( -. A ~< _om -> A ~~ _om ) ) |
17 |
|
ssun2 |
|- B C_ ( A u. B ) |
18 |
|
ssdomg |
|- ( ( A u. B ) e. _V -> ( B C_ ( A u. B ) -> B ~<_ ( A u. B ) ) ) |
19 |
7 17 18
|
mpisyl |
|- ( ( A u. B ) ~~ _om -> B ~<_ ( A u. B ) ) |
20 |
|
domentr |
|- ( ( B ~<_ ( A u. B ) /\ ( A u. B ) ~~ _om ) -> B ~<_ _om ) |
21 |
19 20
|
mpancom |
|- ( ( A u. B ) ~~ _om -> B ~<_ _om ) |
22 |
21
|
anim1i |
|- ( ( ( A u. B ) ~~ _om /\ -. B ~< _om ) -> ( B ~<_ _om /\ -. B ~< _om ) ) |
23 |
|
bren2 |
|- ( B ~~ _om <-> ( B ~<_ _om /\ -. B ~< _om ) ) |
24 |
22 23
|
sylibr |
|- ( ( ( A u. B ) ~~ _om /\ -. B ~< _om ) -> B ~~ _om ) |
25 |
24
|
ex |
|- ( ( A u. B ) ~~ _om -> ( -. B ~< _om -> B ~~ _om ) ) |
26 |
16 25
|
orim12d |
|- ( ( A u. B ) ~~ _om -> ( ( -. A ~< _om \/ -. B ~< _om ) -> ( A ~~ _om \/ B ~~ _om ) ) ) |
27 |
5 26
|
syl5bi |
|- ( ( A u. B ) ~~ _om -> ( -. ( A ~< _om /\ B ~< _om ) -> ( A ~~ _om \/ B ~~ _om ) ) ) |
28 |
4 27
|
mpd |
|- ( ( A u. B ) ~~ _om -> ( A ~~ _om \/ B ~~ _om ) ) |