Step |
Hyp |
Ref |
Expression |
1 |
|
csbeq2 |
|
2 |
1
|
ifeq1d |
|
3 |
2
|
mpteq2dv |
|
4 |
3
|
seqeq3d |
|
5 |
4
|
breq1d |
|
6 |
5
|
anbi2d |
|
7 |
6
|
rexbidv |
|
8 |
|
csbeq2 |
|
9 |
8
|
mpteq2dv |
|
10 |
9
|
seqeq3d |
|
11 |
10
|
fveq1d |
|
12 |
11
|
eqeq2d |
|
13 |
12
|
anbi2d |
|
14 |
13
|
exbidv |
|
15 |
14
|
rexbidv |
|
16 |
7 15
|
orbi12d |
|
17 |
16
|
iotabidv |
|
18 |
|
df-sum |
|
19 |
|
df-sum |
|
20 |
17 18 19
|
3eqtr4g |
|