Step |
Hyp |
Ref |
Expression |
1 |
|
f1oun2prg |
|
2 |
1
|
imp |
|
3 |
2
|
adantr |
|
4 |
|
s4prop |
|
5 |
4
|
adantr |
|
6 |
5
|
eqeq2d |
|
7 |
6
|
biimpa |
|
8 |
7
|
eqcomd |
|
9 |
|
eqidd |
|
10 |
|
eqidd |
|
11 |
8 9 10
|
f1oeq123d |
|
12 |
3 11
|
mpbid |
|
13 |
|
dff1o5 |
|
14 |
|
dff12 |
|
15 |
14
|
bicomi |
|
16 |
15
|
anbi1i |
|
17 |
13 16
|
sylbb2 |
|
18 |
|
ffdm |
|
19 |
18
|
simpld |
|
20 |
19
|
anim1i |
|
21 |
20
|
anim1i |
|
22 |
17 21
|
syl |
|
23 |
|
dff12 |
|
24 |
23
|
anbi1i |
|
25 |
22 24
|
sylibr |
|
26 |
|
dff1o5 |
|
27 |
25 26
|
sylibr |
|
28 |
12 27
|
syl |
|
29 |
28
|
exp31 |
|