Description: Upper bound of the rank of a union. Part of Exercise 30 of Enderton p. 207. (Contributed by NM, 30-Nov-2003)
Ref | Expression | ||
---|---|---|---|
Hypothesis | rankr1b.1 | |
|
Assertion | rankuniss | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | rankr1b.1 | |
|
2 | rankuni | |
|
3 | rankon | |
|
4 | 3 | onordi | |
5 | orduniss | |
|
6 | 4 5 | ax-mp | |
7 | 2 6 | eqsstri | |