Description: Every (possibly proper) subclass of a class A with a well-founded set-like relation R has a minimal element. This is a very strong generalization of tz6.26 and tz7.5 . (Contributed by Scott Fenton, 4-Feb-2011) (Revised by Mario Carneiro, 26-Jun-2015) (Revised by Scott Fenton, 27-Nov-2024)
Ref | Expression | ||
---|---|---|---|
Assertion | frmin | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | frss | |
|
2 | sess2 | |
|
3 | 1 2 | anim12d | |
4 | n0 | |
|
5 | predeq3 | |
|
6 | 5 | eqeq1d | |
7 | 6 | rspcev | |
8 | 7 | ex | |
9 | 8 | adantl | |
10 | predres | |
|
11 | relres | |
|
12 | ssttrcl | |
|
13 | 11 12 | ax-mp | |
14 | predrelss | |
|
15 | 13 14 | ax-mp | |
16 | 10 15 | eqsstri | |
17 | ssn0 | |
|
18 | 16 17 | mpan | |
19 | predss | |
|
20 | 18 19 | jctil | |
21 | dffr4 | |
|
22 | 21 | biimpi | |
23 | ttrclse | |
|
24 | setlikespec | |
|
25 | 23 24 | sylan2 | |
26 | 25 | ancoms | |
27 | sseq1 | |
|
28 | neeq1 | |
|
29 | 27 28 | anbi12d | |
30 | predeq2 | |
|
31 | 30 | eqeq1d | |
32 | 31 | rexeqbi1dv | |
33 | 29 32 | imbi12d | |
34 | 33 | spcgv | |
35 | 34 | impcom | |
36 | 22 26 35 | syl2an | |
37 | 36 | anassrs | |
38 | predres | |
|
39 | predrelss | |
|
40 | 13 39 | ax-mp | |
41 | 38 40 | eqsstri | |
42 | inss1 | |
|
43 | coss1 | |
|
44 | 42 43 | ax-mp | |
45 | coss2 | |
|
46 | 42 45 | ax-mp | |
47 | 44 46 | sstri | |
48 | ttrcltr | |
|
49 | 47 48 | sstri | |
50 | predtrss | |
|
51 | 49 50 | mp3an1 | |
52 | 41 51 | sstrid | |
53 | sspred | |
|
54 | 19 52 53 | sylancr | |
55 | 54 | ancoms | |
56 | 55 | eqeq1d | |
57 | 56 | rexbidva | |
58 | ssrexv | |
|
59 | 19 58 | ax-mp | |
60 | 57 59 | biimtrrdi | |
61 | 60 | adantl | |
62 | 37 61 | syld | |
63 | 20 62 | syl5 | |
64 | 9 63 | pm2.61dne | |
65 | 64 | ex | |
66 | 65 | exlimdv | |
67 | 4 66 | biimtrid | |
68 | 3 67 | syl6com | |
69 | 68 | imp32 | |