`assume()`

is a wrapper for the function with the same name in Maxima. You can find out about the syntax with the usual method of adding a `?`

after the function name:

```
sage: assume?
```

In this case, to indicate that the variable `x`

is in `ZZ`

, you need to type:

```
sage: assume(x, 'integer')
```

Unfortunately, Sage relies on two different backends for symbolic computations, Maxima and Pynac. Each of these uses a different method to indicate domains. We haven't reconciled these through the same interface yet. In order to indicate that a variable is real to Pynac, you can do:

```
sage: var('x', domain=RR)
```

At this moment, Pynac does not have different domains for `ZZ`

or `QQ`

. It only knows about `RR`

, `CC`

and `NN`

.