# alignedat

Used as a nested aligned equation structure with a fixed number of column pairs, often inside another display, with optional top/center/bottom vertical positioning.

https://texform.dev/latex/environments/alignedat

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Alignment](https://texform.dev/latex/topics/alignment) |
| Packages | ams |
| Allowed mode | math |
| Tags | math-alignment, nestable |
| Commonality | low |
| Body mode | math |

## Syntax

### ams

Argument specification: `o m:I`

Used as a nested aligned equation structure with a fixed number of column pairs, often inside another display, with optional top/center/bottom vertical positioning.

## Examples

```latex
\begin{alignedat}{1}a&=b\end{alignedat}
```

[Open in Playground](https://play.texform.dev/?input=%5Cbegin%7Balignedat%7D%7B1%7Da%26%3Db%5Cend%7Balignedat%7D)

```latex
\begin{alignedat}[t]{1}a&=b\end{alignedat}
```

[Open in Playground](https://play.texform.dev/?input=%5Cbegin%7Balignedat%7D%5Bt%5D%7B1%7Da%26%3Db%5Cend%7Balignedat%7D)

## Renderer support

| Package | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- |
| ams | full | partial | full |

## Usage frequency

0.01% of formulas in the measured corpus contain this entry, rank 26 of 31 entries with frequency data.

## In TeXForm

TeXForm reads the environment body in math mode.

## See also

- [alignat](https://texform.dev/latex/environments/alignat)
- [alignat*](https://texform.dev/latex/environments/alignat-star)

## Test cases

### ams

| Input | Case | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- | --- |
| \begin{alignedat}{1} a & b \end{alignedat} | Positive: baseline | Pass | Pass | Pass |
| \begin{alignedat}[a]{1} a & b \end{alignedat} | Positive: vary:o[0] | Pass | Fail | Pass |
| \begin{alignedat}1 a & b \end{alignedat} | Positive: bare[1] | Pass | Pass | Pass |
| \begin{alignedat}{a} a & b \end{alignedat} | Negative: neg:I[1] | Fail | Fail | Fail |