# \abovewithdelims

Plain-TeX infix generalized fraction with explicit rule thickness and explicit left/right delimiters.

https://texform.dev/latex/commands/abovewithdelims

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Fractions and roots](https://texform.dev/latex/topics/fractions-roots) |
| Packages | base |
| Allowed mode | math |
| Tags | discouraged |
| Commonality | low |
| Kind | infix |

## Syntax

### base

Argument specification: `m:D m:D m:L`

Plain-TeX infix generalized fraction with explicit rule thickness and explicit left/right delimiters.

## Examples

```latex
a \abovewithdelims ( ) 1em b
```

[Open in Playground](https://play.texform.dev/?input=a+%5Cabovewithdelims+%28+%29+1em+b)

```latex
a \abovewithdelims ( ) {1em} b
```

[Open in Playground](https://play.texform.dev/?input=a+%5Cabovewithdelims+%28+%29+%7B1em%7D+b)

## Renderer support

| Package | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- |
| base | full | none | full |

## In TeXForm

TeXForm parses this entry as infix syntax; the package determines its argument specification.

### Discouraged in base

This is a plain-TeX infix generalized fraction primitive. LaTeX convention prefers brace-delimited generalized-fraction commands such as \genfrac.

```latex
$1 \abovewithdelims $2 $3 $4 $5 -> \genfrac{$2}{$3}{$4}{}{$1}{$5}
```

\genfrac is the standard LaTeX generalized-fraction command, makes delimiters and thickness explicit, and avoids infix-scope ambiguity.

### [base/abovewithdelims-to-genfrac](https://texform.dev/rules/base/abovewithdelims-to-genfrac)

Rewrite abovewithdelims to an explicit genfrac with delimiters and thickness.

Level: authoring. Fidelity: render.

```latex
#1 \abovewithdelims #2 #3 #4 #5
```

→

```latex
\genfrac{#2}{#3}{#4}{}{#1}{#5}
```

```latex
\sum_{i=0}^{m} a_i t^i \abovewithdelims [ ] 0.8pt \int_0^1 f(x)\,dx
```

→

```latex
\genfrac{[}{]}{0.8pt}{}{\sum_{i=0}^{m} a_i t^i}{\int_0^1 f(x)\,dx}
```

## Equivalent forms

```latex
\genfrac{$2}{$3}{$4}{}{$1}{$5}
```

exact. 

## See also

- [\\above](https://texform.dev/latex/commands/above)
- [\\atop](https://texform.dev/latex/commands/atop)
- [\\atopwithdelims](https://texform.dev/latex/commands/atopwithdelims)
- [\\brace](https://texform.dev/latex/commands/brace)
- [\\brack](https://texform.dev/latex/commands/brack)
- [\\choose](https://texform.dev/latex/commands/choose)
- [\\over](https://texform.dev/latex/commands/over)
- [\\overwithdelims](https://texform.dev/latex/commands/overwithdelims)

## Test cases

### base

| Input | Case | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- | --- |
| a \abovewithdelims ( ( 1pt b | Positive: baseline | Pass | Fail | Pass |
| a \abovewithdelims a ( {1pt} b | Negative: neg:D[0] | Fail | Fail | Fail |
| a \abovewithdelims ( a {1pt} b | Negative: neg:D[1] | Fail | Fail | Fail |
| a \abovewithdelims ( ( {a} b | Negative: neg:L[2] | Fail | Fail | Fail |