# Hypertext Help with LaTeX
Math fonts and styles

## Math styles

The following applies to both LaTeX 2.09 and LaTeX2e.

There are four styles used in typesetting math formulas which affect the size and certain formatting parameters (notably the placement of sub and superscripts on variable size symbols).

- `\textstyle` - default in the running text and in array environment
- `\displaystyle` - default for displayed equations
- `\scriptstyle` - default for first-level sub and superscripts
- `\scriptscriptstyle` - default for higher-level sub and superscripts

All four of these may be used in math mode as declarations to force the type size and formatting to a style other than what would normally be used.

For example, to get a superscript that is the same size as the running text:

      $e^{\textstyle -E/kT}$

As another example, the limits on a summation symbol are normally placed below and above the symbol in `display` style and in normal sub and superscript position in `textstyle`. One could force the below/above placement in running text by using:

     \displaystyle $\sum_{n=0}^\infty x_n$

although it should be noted that this might cause LaTeX to leave extra space between the text lines which might not be desirable.

## LaTeX 2.09 fonts

The regular type style declarations can be used in math mode. They affect only letters (including upper case Greek letters) but not symbols (or lower case Greek letters). Two additional style declarations which can be used only in math mode are

- `\mit`
- `\cal`

The former is math italic style; it spaces letters as if they were words, however, not as if they were each separate math symbols. The latter produces upper case calligraphic letters.

## LaTeX2e math fonts

The following declarations change the style only of letters, numbers, and uppercase Greek.

- `\mathit` - same as `\mit` in 2.09 (see above)
- `\mathrm` - Roman
- `\mathbf` - Bold face
- `\mathsf` - San Serif
- `\mathtt` - Typewriter style
- `\mathcal` - Calligraphic

All of these produce spacing appropriate for text; they do not interpret each letter as a separate math symbol.

The `\boldmath` declaration causes everything (including symbols) in a formula to be in a bold font. Note that this differs somewhat from the same declaration in 2.09 which did not affect some symbols.

Related topics

- Math Formulas
- Typefaces
  - Styles
  - Sizes
  - LaTeX2e fonts
- Variable size symbols
- Miscellaneous symbols

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