\overbrace command puts a (stretchy) over-brace over the argument. Can use '^' to place an optional superscript over the overbrace; can use ‘_’ to place an optional subscript below the argument.

EXAMPLE

```
\overbrace{x + \cdots + x}^{n\rm\ times}_{\text{(note here)}}
```
$ \overbrace{x + \cdots + x}^{n\rm\ times}_{\text{(note here)}} $