I am looking for a pipe symbol that can be made to vary in height automatically.

One of the common ways of writing "such that" in mathematics is with the pipe symbol (|). The pipe can be represented in LaTeX directly as the character | or as `\vert`

, but neither of these expands vertically in math presentation mode. I can adjust it manually this way:

```
\[\mathcal{H}=\left\lbrace h(x)=\sum_{i=0}^{k-1}a_{i}x_{i}\mod m\ \Bigg\vert
\ a_{i}\in\mathbb{Z}_{m^{k}}\right\rbrace\]
```

but I am looking for a true variable-sized option, parallel to `\lbrace`

etc.

The `amsmath`

package provides `\lvert`

and `\rvert`

, but I do not find them expanding as expected, and the `amsmath`

documentation specifies that they should be used as binary delimiters (one on each side of something else), rather than alone.

## Best Answer

You can use the

`braket`

package for this kind of thing.It defines a

`\Set`

macro which automatically puts its contents in variable sized braces, and any instance of the`|`

symbol inside will adjust accordingly. This solution also has the advantage of making your source code more semantic.