# \pb

Shorthand for \\poissonbracket, used in classical mechanics to denote the Poisson bracket {f,g}

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

## Metadata

| Field | Value |
| --- | --- |
| Topic | [Physics: quantities](https://texform.dev/latex/topics/physics-quantities) |
| Packages | physics |
| Allowed mode | math |
| Tags |  |
| Commonality | low |
| Kind | prefix |

## Syntax

### physics

Argument specification: `s m{} m`

Shorthand for \\poissonbracket, used in classical mechanics to denote the Poisson bracket {f,g}

## Examples

```latex
\pb{f}{g}
```

[Open in Playground](https://play.texform.dev/?input=%5Cpb%7Bf%7D%7Bg%7D)

## Renderer support

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

## In TeXForm

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

### Expands to (physics)

```latex
\pb{f}{g}
```

→

```latex
\left\{f,g\right\}
```

With star: \{f,g\} without \left/\right. With optional \big, \Big, \bigg, or \Bigg prefix: uses corresponding \bigl\{...\bigr\} sizing.

### [physics/poisson-bracket-expand](https://texform.dev/rules/physics/poisson-bracket-expand)

Expand poisson brackets to explicit brace fences.

Level: faithful. Fidelity: render.

```latex
\pb{#1}{#2}
```

→

```latex
\left\{#1,#2\right\}
```

```latex
\pb{q_i}{p_j}=\delta_{ij}
```

→

```latex
\left\{q_i,p_j\right\}=\delta_{ij}
```

## Equivalent forms

```latex
\poissonbracket{f}{g}
```

exact. 

## See also

- [\\acomm](https://texform.dev/latex/commands/acomm)
- [\\anticommutator](https://texform.dev/latex/commands/anticommutator)
- [\\comm](https://texform.dev/latex/commands/comm)
- [\\commutator](https://texform.dev/latex/commands/commutator)
- [\\poissonbracket](https://texform.dev/latex/commands/poissonbracket)

## Test cases

### physics

| Input | Case | MathJax | KaTeX | XeTeX |
| --- | --- | --- | --- | --- |
| \pb{a}{b} | Positive: baseline | Pass | Fail | Pass |
| \pb*{a}{b} | Positive: vary:s[0] | Pass | Fail | Pass |
| \pb{a}b | Positive: bare[2] | Pass | Fail | Pass |