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Metamath Proof Explorer
Theorem 0xr
Description: Zero is an extended real. (Contributed by Mario Carneiro, 15-Jun-2014)
|
|
Ref |
Expression |
|
Assertion |
0xr |
|- 0 e. RR* |
Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
ressxr |
|- RR C_ RR* |
| 2 |
|
0re |
|- 0 e. RR |
| 3 |
1 2
|
sselii |
|- 0 e. RR* |