Step |
Hyp |
Ref |
Expression |
1 |
|
frege116.x |
|
2 |
|
dffrege115 |
|
3 |
1
|
frege68c |
|
4 |
|
sbcal |
|
5 |
|
sbcimg |
|
6 |
1 5
|
ax-mp |
|
7 |
|
sbcbr2g |
|
8 |
1 7
|
ax-mp |
|
9 |
|
csbvarg |
|
10 |
1 9
|
ax-mp |
|
11 |
10
|
breq2i |
|
12 |
8 11
|
bitri |
|
13 |
|
sbcal |
|
14 |
|
sbcimg |
|
15 |
1 14
|
ax-mp |
|
16 |
|
sbcg |
|
17 |
1 16
|
ax-mp |
|
18 |
|
sbceq2g |
|
19 |
1 18
|
ax-mp |
|
20 |
10
|
eqeq2i |
|
21 |
19 20
|
bitri |
|
22 |
17 21
|
imbi12i |
|
23 |
15 22
|
bitri |
|
24 |
23
|
albii |
|
25 |
13 24
|
bitri |
|
26 |
12 25
|
imbi12i |
|
27 |
6 26
|
bitri |
|
28 |
27
|
albii |
|
29 |
4 28
|
bitri |
|
30 |
3 29
|
syl6ib |
|
31 |
2 30
|
ax-mp |
|