Description: Cartesian products with disjoint sets are disjoint. (Contributed by NM, 13-Sep-2004)
Ref | Expression | ||
---|---|---|---|
Assertion | xpdisj1 | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | xpeq1 | |
|
2 | inxp | |
|
3 | 0xp | |
|
4 | 3 | eqcomi | |
5 | 1 2 4 | 3eqtr4g | |