Description: The union of singletons consisting of length 3 strings which have distinct first and third symbols are disjunct. (Contributed by AV, 17-May-2021)
Ref | Expression | ||
---|---|---|---|
Assertion | s3iunsndisj | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | orc | |
|
2 | 1 | a1d | |
3 | eliun | |
|
4 | velsn | |
|
5 | eqeq1 | |
|
6 | 5 | adantl | |
7 | s3cli | |
|
8 | elex | |
|
9 | elex | |
|
10 | 9 | adantl | |
11 | 8 10 | anim12ci | |
12 | elex | |
|
13 | 12 | adantl | |
14 | 11 13 | anim12i | |
15 | df-3an | |
|
16 | 14 15 | sylibr | |
17 | eqwrds3 | |
|
18 | 7 16 17 | sylancr | |
19 | s3fv0 | |
|
20 | 19 | elv | |
21 | simp1 | |
|
22 | 20 21 | eqtr3id | |
23 | 22 | adantl | |
24 | 18 23 | syl6bi | |
25 | 24 | adantr | |
26 | 6 25 | sylbid | |
27 | 26 | ancoms | |
28 | 27 | con3d | |
29 | 28 | exp32 | |
30 | 29 | com14 | |
31 | 30 | imp | |
32 | 31 | expd | |
33 | 32 | com34 | |
34 | 33 | imp | |
35 | 4 34 | biimtrid | |
36 | 35 | imp | |
37 | 36 | imp | |
38 | velsn | |
|
39 | 37 38 | sylnibr | |
40 | 39 | nrexdv | |
41 | eliun | |
|
42 | 40 41 | sylnibr | |
43 | 42 | rexlimdva2 | |
44 | 3 43 | biimtrid | |
45 | 44 | ralrimiv | |
46 | eqidd | |
|
47 | eqidd | |
|
48 | id | |
|
49 | 46 47 48 | s3eqd | |
50 | 49 | sneqd | |
51 | 50 | cbviunv | |
52 | 51 | eleq2i | |
53 | 52 | notbii | |
54 | 53 | ralbii | |
55 | 45 54 | sylibr | |
56 | disj | |
|
57 | 55 56 | sylibr | |
58 | 57 | olcd | |
59 | 58 | ex | |
60 | 2 59 | pm2.61i | |
61 | 60 | ralrimivva | |
62 | sneq | |
|
63 | 62 | difeq2d | |
64 | id | |
|
65 | eqidd | |
|
66 | eqidd | |
|
67 | 64 65 66 | s3eqd | |
68 | 67 | sneqd | |
69 | 63 68 | disjiunb | |
70 | 61 69 | sylibr | |