Step |
Hyp |
Ref |
Expression |
1 |
|
ftc2ditg.x |
|
2 |
|
ftc2ditg.y |
|
3 |
|
ftc2ditg.a |
|
4 |
|
ftc2ditg.b |
|
5 |
|
ftc2ditg.c |
|
6 |
|
ftc2ditg.i |
|
7 |
|
ftc2ditg.f |
|
8 |
|
iccssre |
|
9 |
1 2 8
|
syl2anc |
|
10 |
9 3
|
sseldd |
|
11 |
9 4
|
sseldd |
|
12 |
1 2 3 4 5 6 7
|
ftc2ditglem |
|
13 |
|
fvexd |
|
14 |
|
cncff |
|
15 |
5 14
|
syl |
|
16 |
15
|
feqmptd |
|
17 |
16 6
|
eqeltrrd |
|
18 |
1 2 4 3 13 17
|
ditgswap |
|
19 |
18
|
adantr |
|
20 |
1 2 4 3 5 6 7
|
ftc2ditglem |
|
21 |
20
|
negeqd |
|
22 |
|
cncff |
|
23 |
7 22
|
syl |
|
24 |
23 3
|
ffvelrnd |
|
25 |
23 4
|
ffvelrnd |
|
26 |
24 25
|
negsubdi2d |
|
27 |
26
|
adantr |
|
28 |
19 21 27
|
3eqtrd |
|
29 |
10 11 12 28
|
lecasei |
|