Metamath Proof Explorer
Description: The negative of a nonzero number is nonzero. (Contributed by NM, 30-Jul-2004)
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|
Ref |
Expression |
|
Hypotheses |
negidi.1 |
|
|
|
negne0i.2 |
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Assertion |
negne0i |
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Proof
| Step |
Hyp |
Ref |
Expression |
| 1 |
|
negidi.1 |
|
| 2 |
|
negne0i.2 |
|
| 3 |
1
|
negne0bi |
|
| 4 |
2 3
|
mpbi |
|