Description: Lemma 4 for 3wlkd . (Contributed by Alexander van der Vekens, 11-Nov-2017) (Revised by AV, 7-Feb-2021)
Ref | Expression | ||
---|---|---|---|
Hypotheses | 3wlkd.p | |
|
3wlkd.f | |
||
3wlkd.s | |
||
Assertion | 3wlkdlem4 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | 3wlkd.p | |
|
2 | 3wlkd.f | |
|
3 | 3wlkd.s | |
|
4 | 1 2 3 | 3wlkdlem3 | |
5 | simpl | |
|
6 | 5 | eleq1d | |
7 | simpr | |
|
8 | 7 | eleq1d | |
9 | 6 8 | anbi12d | |
10 | 9 | biimparc | |
11 | c0ex | |
|
12 | 1ex | |
|
13 | 11 12 | pm3.2i | |
14 | fveq2 | |
|
15 | 14 | eleq1d | |
16 | fveq2 | |
|
17 | 16 | eleq1d | |
18 | 15 17 | ralprg | |
19 | 13 18 | mp1i | |
20 | 10 19 | mpbird | |
21 | 20 | ex | |
22 | simpl | |
|
23 | 22 | eleq1d | |
24 | simpr | |
|
25 | 24 | eleq1d | |
26 | 23 25 | anbi12d | |
27 | 26 | biimparc | |
28 | 2ex | |
|
29 | 3ex | |
|
30 | 28 29 | pm3.2i | |
31 | fveq2 | |
|
32 | 31 | eleq1d | |
33 | fveq2 | |
|
34 | 33 | eleq1d | |
35 | 32 34 | ralprg | |
36 | 30 35 | mp1i | |
37 | 27 36 | mpbird | |
38 | 37 | ex | |
39 | 21 38 | im2anan9 | |
40 | 3 4 39 | sylc | |
41 | 2 | fveq2i | |
42 | s3len | |
|
43 | 41 42 | eqtri | |
44 | 43 | oveq2i | |
45 | fz0to3un2pr | |
|
46 | 44 45 | eqtri | |
47 | 46 | raleqi | |
48 | ralunb | |
|
49 | 47 48 | bitri | |
50 | 40 49 | sylibr | |