Metamath Proof Explorer
Description: Contrapositive inference for inequality. (Contributed by NM, 23-May-2007) (Proof shortened by Andrew Salmon, 25-May-2011)
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|
Ref |
Expression |
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Hypothesis |
necon3ai.1 |
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Assertion |
necon3ai |
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Proof
Step |
Hyp |
Ref |
Expression |
1 |
|
necon3ai.1 |
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2 |
|
nne |
|
3 |
1 2
|
sylibr |
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4 |
3
|
con2i |
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