Description: An ordered pair commutes iff its members are equal. (Contributed by NM, 28-May-2009)
Ref | Expression | ||
---|---|---|---|
Hypotheses | opcom.1 | |
|
opcom.2 | |
||
Assertion | opcom | |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | opcom.1 | |
|
2 | opcom.2 | |
|
3 | 1 2 | opth | |
4 | eqcom | |
|
5 | 4 | anbi2i | |
6 | anidm | |
|
7 | 3 5 6 | 3bitri | |