6

As the title says, does LaTeX have this special symbol:

::=

I tried to look at some cheat-sheets and http://detexify.kirelabs.org/classify.html but could not find it.

16

Yes, it is called \Coloneqq and it's defined by the mathtools package, which is an extension of amsmath.

MWE

\documentclass{article}
\usepackage{mathtools}

\begin{document}
\[
\Coloneqq
\]
\end{document} 

enter image description here

The package also provides other symbols like the above one (see subsubsection 3.7.3 of the documentation) including \vcentcolon which is a colon properly vertically centered.

Moreover, issuing

\mathtoolsset{centercolon}

you can have all your math colons (including the \colon command) properly vertically centered.

Example:

\documentclass{article}
\usepackage{mathtools}
\mathtoolsset{centercolon}

\begin{document}
\[
\colon \quad : \quad \coloneqq \quad \Coloneqq
\]
\end{document} 

enter image description here

5

Package colonequals provides such symbols with properly vertically centered colons:

\documentclass{article}
\usepackage{colonequals}

\begin{document}
\[ A \coloncolonequals B \]
\end{document}

Result

OpenType fonts

If the TeX engine supports OpenType fonts (LuaTeX, XeTeX), then the symbol can be used directly as Unicode symbol (U+2A74) or macro \Coloneq, if package unicode-math with a font, which contains this symbol.

When testing fonts, \tracinglostchars=2 is useful, because then missing characters are also logged on the screen, e.g.:

Missing character: There is no ⩴ (U+2A74) in font "[latinmodern-math]:mode=base;script=math;language=DFLT;"!

Asana-Math

\documentclass{article}
\usepackage{unicode-math}
\setmathfont{Asana-Math.otf} 
\begin{document}
  \[ A \Coloneq B \]
\end{document}

Result for Asana-Math

XITS Math

\setmathfont{xits-math.otf}

Result for XITS Math

2

If you needn't to use any packages, you can define the symbol:

\def\cceq{\mathrel{\vcenter{\hbox{::}}{=}}}

$$ A \cceq B $$
\bye

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.