Description: The rank of an ordered pair. Part of Exercise 4 of Kunen p. 107. (Contributed by NM, 13-Sep-2006) (Revised by Mario Carneiro, 17-Nov-2014)
Ref | Expression | ||
---|---|---|---|
Hypotheses | ranksn.1 | |
|
rankun.2 | |
||
Assertion | rankop | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ranksn.1 | |
|
2 | rankun.2 | |
|
3 | unir1 | |
|
4 | 1 3 | eleqtrri | |
5 | 2 3 | eleqtrri | |
6 | rankopb | |
|
7 | 4 5 6 | mp2an | |