Description: An equivalence class according to .~ . (Contributed by Alexander van der Vekens, 12-Apr-2018) (Revised by AV, 30-Apr-2021)
Ref | Expression | ||
---|---|---|---|
Hypotheses | erclwwlkn.w | |
|
erclwwlkn.r | |
||
Assertion | eclclwwlkn1 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | erclwwlkn.w | |
|
2 | erclwwlkn.r | |
|
3 | elqsecl | |
|
4 | 1 2 | erclwwlknsym | |
5 | 1 2 | erclwwlknsym | |
6 | 4 5 | impbii | |
7 | 6 | a1i | |
8 | 7 | abbidv | |
9 | 1 2 | erclwwlkneq | |
10 | 9 | el2v | |
11 | 10 | a1i | |
12 | 11 | abbidv | |
13 | 3anan12 | |
|
14 | ibar | |
|
15 | 14 | bicomd | |
16 | 15 | adantl | |
17 | 13 16 | bitrid | |
18 | 17 | abbidv | |
19 | df-rab | |
|
20 | 18 19 | eqtr4di | |
21 | 8 12 20 | 3eqtrd | |
22 | 21 | eqeq2d | |
23 | 22 | rexbidva | |
24 | 3 23 | bitrd | |