Description: Equality theorem for Cartesian product. (Contributed by NM, 4-Jul-1994)
Ref | Expression | ||
---|---|---|---|
Assertion | xpeq1 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eleq2 | |
|
2 | 1 | anbi1d | |
3 | 2 | opabbidv | |
4 | df-xp | |
|
5 | df-xp | |
|
6 | 3 4 5 | 3eqtr4g | |