### The Maxima on-line user's manual

Algebra Calculator

#### Features

-- Declaration: features Maxima recognizes certain mathematical properties of functions and variables. These are called "features".

`declare (<x>, <foo>)` gives the property <foo> to the function or variable <x>.

`declare (<foo>, feature)` declares a new feature <foo>. For example, `declare ([red, green, blue], feature)` declares three new features, `red`, `green`, and `blue`.

The predicate `featurep (<x>, <foo>)` returns `true` if <x> has the <foo> property, and `false` otherwise.

The infolist `features` is a list of known features. These are `integer`, `noninteger`, `even`, `odd`, `rational`, `irrational`, `real`, `imaginary`, `complex`, `analytic`, `increasing`, `decreasing`, `oddfun`, `evenfun`, `posfun`, `commutative`, `lassociative`, `rassociative`, `symmetric`, and `antisymmetric`, plus any user-defined features.

`features` is a list of mathematical features. There is also a list of non-mathematical, system-dependent features. See `status`.

```(%o1)                                true
(%i2) ```

? features;

Calculate

? features;

Calculate