Step |
Hyp |
Ref |
Expression |
1 |
|
3anass |
|
2 |
|
3anan12 |
|
3 |
|
3anrev |
|
4 |
|
3anass |
|
5 |
3 4
|
bitri |
|
6 |
1 2 5
|
3anbi123i |
|
7 |
|
3an6 |
|
8 |
|
anass |
|
9 |
8
|
anbi2i |
|
10 |
|
an42 |
|
11 |
9 10
|
bitri |
|
12 |
|
anass |
|
13 |
|
anass |
|
14 |
11 12 13
|
3bitr4i |
|
15 |
14
|
anbi1i |
|
16 |
|
anass |
|
17 |
|
anass |
|
18 |
15 16 17
|
3bitr3i |
|
19 |
|
df-3an |
|
20 |
|
df-3an |
|
21 |
18 19 20
|
3bitr4i |
|
22 |
21
|
anbi2i |
|
23 |
6 7 22
|
3bitri |
|