Description: Existence of union is equivalent to existence of its components. (Contributed by NM, 11-Jun-1998)
Ref | Expression | ||
---|---|---|---|
Assertion | unexb |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | unexg | ||
2 | ssun1 | ||
3 | ssexg | ||
4 | 2 3 | mpan | |
5 | ssun2 | ||
6 | ssexg | ||
7 | 5 6 | mpan | |
8 | 4 7 | jca | |
9 | 1 8 | impbii |