Metamath Proof Explorer
Description: Commutation law for triple conjunction. (Contributed by NM, 21-Apr-1994)
(Revised to shorten 3anrot by Wolf Lammen, 9-Jun-2022.)
|
|
Ref |
Expression |
|
Assertion |
3ancomb |
|
Proof
Step |
Hyp |
Ref |
Expression |
1 |
|
df-3an |
|
2 |
|
3anan32 |
|
3 |
1 2
|
bitr4i |
|