# Documentation

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# Dom::Expression

Domain of all objects of basic type

MATLAB live scripts support most MuPAD functionality, though there are some differences. For more information, see Convert MuPAD Notebooks to MATLAB Live Scripts.

## Syntax

```Dom::Expression(`x`)
```

## Description

`Dom::Expression` comprises all objects only consisting of operands of built-in types.

`Dom::Expression` is a façade domain: it has no domain elements, but uses system representation.

Unlike `Dom::ExpressionField`, `Dom::Expression` does not belong to any arithmetical category, and its elements need not be arithmetical expressions.

`Dom::Expression` mainly serves as a super-domain to `Dom::ArithmeticalExpression`; it rarely makes sense to use it directly.

## Superdomain

`Dom::BaseDomain`

## Axioms

`Ax::systemRep`, `Ax::efficientOperation``("_divide")`, `Ax::efficientOperation``("_mult")`, `Ax::efficientOperation``("_invert")`

## Categories

`Cat::BaseCategory`

## Examples

### Example 1

Almost every MuPAD® object can be converted to an expression. Objects of basic type are expressions.

`Dom::Expression([3, array(1..2), rectform(exp(I))])`
``` ```

The `convert` method flattens its argument: hence expression sequences are not allowed.

`Dom::Expression((3, x))`
```Error: The number of arguments is incorrect. [expr] Evaluating: Dom::Expression::new ```

## Parameters

 `x` An object of basic type consisting only of operands of built-in types, or any other object convertible to such using `expr`.

## Entries

 "randomIdent" an identifier used for creating random elements

## Methods

expand all

#### Conversion Methods

`convert(x)`

`convert_to(x, T)`

`expr(x)`

`testtype(x, Dom::Expression)`

This method overloads `testtype`; since `Dom::Expression` has no domain elements, the overloading can only be caused by the second argument.

`float(x)`

#### Technical Methods

`subs(x, s, …)`

`subsex(x, s, …)`

`random()`