# Hypertext Help with LaTeX
Variable size symbols

The size of some mathematical symbols, notably summation signs, product signs, and integral signs, depends on the environment in which they appear (i.e., `displaymath` as opposed to `math` environments; see Math Formulas and Math Fonts and Styles).

These include

- `\sum` a summation sign (capital sigma)
- `\prod` a product (capital pi)
- `\coprod` a coproduct (inverted capital pi)
- `\int` an integral sign
- `\oint` a surface (circular) integral sign
- `\bigcup` big "U"
- `\bigcap` big inverted "U"
- `\bigvee` big "V"
- `\bigwedge` big inverted "V"
- `\bigodot` big "O" with dot at center
- `\bigotimes` big "O" with cross inside
- `\bigoplus` big "O" with a + inside
- `\biguplus` big "U" with a + inside

The `\sqrt` command also produces a variable size symbol appropriate for the size of hte radicand argument.

The "limits" associated with these symbols are entered as subscripts for entries appearing below the symbol and as superscripts for entries appearing above the symbol. For example the sum from n=0 to infinity of xn would be entered as

      \sum_{n=0}^{\infty} x_{n}

The actual placement of the limits depends on whether this is in `displaymath` mode in which case they are placed below/above or in `math` mode in running text in which case they are placed as regular subscripts and superscripts.

Note that it is possible to treat several of these symbols (a common example would be a double sum) as a single symbol for placing limits above and/or below by using the `\mathop` command.

"Hats" and "tildes" over symbols which stretch (as best they can) to the correct size for their arguments are produced by `\widehat` and `\widetilde`.

Related topics:

- Delimiters can be made variable sized
- Math fonts and styles

- Math Formulas
- Math Symbols
- Math Miscellany
- Arrows
- Binary and relational operators
- Math function symbols
- Miscellaneous symbols

- `\left`
- `\right`
- `\sqrt`
- `\stackrel` and `\mathop`

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