Description: A helpful lemma for showing that certain sets generate filters. (Contributed by Jeff Hankins, 3-Sep-2009) (Revised by Stefan O'Rear, 2-Aug-2015)
Ref | Expression | ||
---|---|---|---|
Assertion | fbunfip | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elfiun | |
|
2 | 1 | notbid | |
3 | 3ioran | |
|
4 | df-3an | |
|
5 | 3 4 | bitr2i | |
6 | 2 5 | bitr4di | |
7 | nesym | |
|
8 | 7 | ralbii | |
9 | ralnex | |
|
10 | 8 9 | bitri | |
11 | 10 | ralbii | |
12 | ralnex | |
|
13 | 11 12 | bitri | |
14 | fbasfip | |
|
15 | fbasfip | |
|
16 | 14 15 | anim12i | |
17 | 16 | biantrurd | |
18 | 13 17 | bitr2id | |
19 | ssfii | |
|
20 | ssralv | |
|
21 | 19 20 | syl | |
22 | ssfii | |
|
23 | ssralv | |
|
24 | 22 23 | syl | |
25 | 24 | ralimdv | |
26 | 21 25 | sylan9 | |
27 | ineq1 | |
|
28 | 27 | neeq1d | |
29 | ineq2 | |
|
30 | 29 | neeq1d | |
31 | 28 30 | cbvral2vw | |
32 | fbssfi | |
|
33 | fbssfi | |
|
34 | r19.29 | |
|
35 | r19.29 | |
|
36 | ss2in | |
|
37 | sseq2 | |
|
38 | ss0 | |
|
39 | 37 38 | syl6bi | |
40 | 36 39 | syl5com | |
41 | 40 | necon3d | |
42 | 41 | ex | |
43 | 42 | com13 | |
44 | 43 | imp | |
45 | 44 | rexlimivw | |
46 | 35 45 | syl | |
47 | 46 | impancom | |
48 | 47 | rexlimivw | |
49 | 34 48 | syl | |
50 | 49 | expimpd | |
51 | 50 | com12 | |
52 | 32 33 51 | syl2an | |
53 | 52 | an4s | |
54 | 53 | ralrimdvva | |
55 | 31 54 | biimtrid | |
56 | 26 55 | impbid | |
57 | 6 18 56 | 3bitrd | |