Step |
Hyp |
Ref |
Expression |
1 |
|
eloni |
|- ( B e. On -> Ord B ) |
2 |
|
ordgt0ge1 |
|- ( Ord B -> ( (/) e. B <-> 1o C_ B ) ) |
3 |
1 2
|
syl |
|- ( B e. On -> ( (/) e. B <-> 1o C_ B ) ) |
4 |
3
|
adantl |
|- ( ( A e. On /\ B e. On ) -> ( (/) e. B <-> 1o C_ B ) ) |
5 |
|
1on |
|- 1o e. On |
6 |
|
omwordi |
|- ( ( 1o e. On /\ B e. On /\ A e. On ) -> ( 1o C_ B -> ( A .o 1o ) C_ ( A .o B ) ) ) |
7 |
5 6
|
mp3an1 |
|- ( ( B e. On /\ A e. On ) -> ( 1o C_ B -> ( A .o 1o ) C_ ( A .o B ) ) ) |
8 |
7
|
ancoms |
|- ( ( A e. On /\ B e. On ) -> ( 1o C_ B -> ( A .o 1o ) C_ ( A .o B ) ) ) |
9 |
|
om1 |
|- ( A e. On -> ( A .o 1o ) = A ) |
10 |
9
|
adantr |
|- ( ( A e. On /\ B e. On ) -> ( A .o 1o ) = A ) |
11 |
10
|
sseq1d |
|- ( ( A e. On /\ B e. On ) -> ( ( A .o 1o ) C_ ( A .o B ) <-> A C_ ( A .o B ) ) ) |
12 |
8 11
|
sylibd |
|- ( ( A e. On /\ B e. On ) -> ( 1o C_ B -> A C_ ( A .o B ) ) ) |
13 |
4 12
|
sylbid |
|- ( ( A e. On /\ B e. On ) -> ( (/) e. B -> A C_ ( A .o B ) ) ) |
14 |
13
|
imp |
|- ( ( ( A e. On /\ B e. On ) /\ (/) e. B ) -> A C_ ( A .o B ) ) |