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Metamath Proof Explorer
Theorem 1ex
Description: One is a set. (Contributed by David A. Wheeler, 7-Jul-2016)
|
|
Ref |
Expression |
|
Assertion |
1ex |
|- 1 e. _V |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
ax-1cn |
|- 1 e. CC |
| 2 |
1
|
elexi |
|- 1 e. _V |