Description: Equality theorem for the classes of cosets by A and B . (Contributed by Peter Mazsa, 9-Jan-2018)
Ref | Expression | ||
---|---|---|---|
Assertion | cosseq |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | breq | ||
2 | breq | ||
3 | 1 2 | anbi12d | |
4 | 3 | exbidv | |
5 | 4 | opabbidv | |
6 | df-coss | ||
7 | df-coss | ||
8 | 5 6 7 | 3eqtr4g |