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.
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 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
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.