Metamath Proof Explorer
Description: Shorter proof of prfi using ax-un . (Contributed by NM, 22-Aug-2008)
(Proof modification is discouraged.) (New usage is discouraged.)
|
|
Ref |
Expression |
|
Assertion |
prfiALT |
|
Proof
Step |
Hyp |
Ref |
Expression |
1 |
|
df-pr |
|
2 |
|
snfi |
|
3 |
|
snfi |
|
4 |
|
unfi |
|
5 |
2 3 4
|
mp2an |
|
6 |
1 5
|
eqeltri |
|