How to look up a symbol or identify a math alphabet?

Question

I know what my symbol or character looks like, but I don't know what the command is or which math alphabet it came from. How do I go about finding this out?

Answer 1

1. You can look things up in the Comprehensive LaTeX symbols list. It can usually be easily accessed with texdoc symbols or texdoc symbols-a4 (in MiKTeX the latter only).

2. Another good option is to try Detexify, which allows you to draw the symbol and tries to recognize what you've drawn. Here is a screenshot:

   

3. If you are using the package unicode-math, then besides using any Unicode character list, the list of all supported symbols (texdoc unimath-symbols) is very useful as it also lists which symbols are available in the various fonts.

Answer 2

Theres lots of ways of doing this, but the two I've found to be most useful are these:

• Detexify Allows you to draw the symbol, and then guesses based on similar symbols. This is great for me because I don't always remember the name of the symbol, and even if I know the name, I may not have the correct name.

• AMS LaTeX Short Math Guide This short pdf gives an overview of AMS LaTeX functionality, and includes a pretty thorough list of most of the math symbols (un)commonly used in proofs and formulas.

Answer 3

The old school way is to look it up in the Comprehensive LaTeX Symbol List (warning: 4 MB PDF file).

The new hotness is to use DeTeXify which uses handwriting recognition to look the symbol up for you.

DeTeXify even comes in an iPhone/Andriod app- you can get a free version or pay for one. The only difference is that with the paid app you are making a donation to the developer- the feature set is exactly the same.

The author is planning to work on a mobile version of the website that will supplant these apps.

Answer 4

I often look up the relevant topic on Wikipedia, (e.g. Set theory) and look at the source there. Wikipedia uses LaTeX for math markup as well.

Answer 5

For uncommon symbols, instead of search documentation on-line or in a big PDF to find packages and commands to include in my code, I have found useful sometimes to compile the whole table of characters of a font (even in the working document) to quickly find, for example, the skull of the omding font that is \char194. Of course, you have first to know that you have a font file with that name (omding.tfm) but then is easy:

\documentclass{article}
\usepackage{fonttable}
\begin{document}
\fonttable{omding}
\font\omding=omding
\omding  \char194
\end{document}

You can also search for a skull the in Comprehensive LaTeX symbols list, or paint a skull in Detexify, or remember the easy command "\skull" (and do not forget load the skull package and enter in math mode) o try to find a \dingbat or \ding{whatever}... but when I want a skull (really never) must be that of white bones (just try the other methods if you don't know what I mean).

Answer 6

There's also an iPhone app for Detexify, which I've used occasionally, for some reason ...

Links (on the US iTunes App Store): free version and supporter version ($0.99, same functionality).

Answer 7

This reference has yet to fail me; it has all the symbols typeset along with the \foo command needed to generate them. There's also this PDF, which is considerably better put-together and covers other symbols besides the base math ones

Answer 8

The LaTeX wikibook Mathematics section has been very helpful for me.

Answer 9

Some utilities for lookup symbols in Unicode:

• ent2latex: A Perl script to translate Unicode symbols to LaTeX commands. (However, it doesn't utilize math fonts.)

• kcharset: A KDE application to lookup Unicode. (Well, you can input some symbols in Unicode directly, or lookup the corresponding LaTeX command by ent2latex.)