# I What is the opposite of epsilon

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1. Jun 10, 2016

### Pjpic

Is there a notation for the opposite of epsilon (infinitesimal) in the way that infinity is the opposite of zero?

2. Jun 10, 2016

### Staff: Mentor

I don't think there is a definitive term, I've seen people use these terms:
- immeasureable
- infinite

3. Jun 10, 2016

### Ssnow

For every $\varepsilon >0$ ''very small'' you have $\varepsilon^{-1}=\frac{1}{\varepsilon}$ is ''very big'', in general there is no a preferred symbol to denote this ...

4. Jun 10, 2016

### micromass

Staff Emeritus
Usually, people like to use capital letters for this, such as $H$ or $N$.

5. Jun 10, 2016

### Staff: Mentor

What does the H or N stand for?

6. Jun 10, 2016

### Staff: Mentor

Perhaps $N$ for number such as $N(ε)$. I've also seen $C$ for a constant. But I've never seen a huge $H$.

7. Jun 10, 2016

### wrobel

"The nightmare of mathematician is a sequence $\varepsilon_n$ that tends to infinity, as $n \to 0$"
Paul Halmos

8. Jun 11, 2016

### Aniruddha@94

The opposite of infinity is not zero, it's $\varepsilon$.
Source : This Numberphile video

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Depends how you define "opposite". If you mean additive inverse, then $-\infty$ would be the opposite of $\infty$, and $-\varepsilon$ for $\varepsilon$. If by "opposite" you mean multiplicative inverse, then the opposite of $\varepsilon$ would be $\infty$. Zero, on the other hand doesn't have a multiplicative inverse, so maybe we can say it doesn't have an opposite.