## Epsilon

Epsilon is $(n-4)$, where $n$ is the space-time dimension.

`Epsilon` stands for a small positive number.

### See also

[Overview](Extra/FeynCalc.md), [Series2](Series2.md).

### Examples

```mathematica
Epsilon
```

$$\varepsilon$$

Epsilon has no functional properties, but some upvalues are changed:

```mathematica
{Re[Epsilon] > -4, Re[Epsilon] > -3, Re[Epsilon] > -2, Re[Epsilon] > -1, Re[Epsilon] > 0}
```

$$\{\text{True},\text{True},\text{True},\text{True},\text{True}\}$$