Metamath Proof Explorer
Description: Plus infinity exists. (Contributed by David A. Wheeler, 8-Dec-2018)
(Revised by Steven Nguyen, 7-Dec-2022)
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|
Ref |
Expression |
|
Assertion |
pnfex |
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Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
df-pnf |
|
| 2 |
|
cnex |
|
| 3 |
2
|
uniex |
|
| 4 |
3
|
pwex |
|
| 5 |
1 4
|
eqeltri |
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