# How to make another kappa

Good afternoon! I would like you to tell me how to make another "kappa"? I mean, how to make the default kappa look like the \ae symbol? I need to use such variant in formula but I always get warnings when using "\ae" in equations. What should I do? I tried to use \varkappa but I don't like how it looks. Thank you for your attention and also sorry for my Enlgish.

\newcommand{\Kappa}{\text{\ae}}


The problem is that inside \begin{align}\end{align} it looks like on the screen. Inside other environments such as [ ] or  it looks like the normal kappa: ae. What should I do?

I tried to use "mbox" instead of "text" but the problem remains. Only here this letter looks wrong. Is it possible to avoid these misunderstandings?

• You can override the \kappa command to call the \ae command. Is that what you're looking for? Jul 16 '15 at 14:02
• Yep, that sounds like what I really needed to find. Thank you. Jul 16 '15 at 14:24
• Could you mark an answer as accepted or post your solution and accept that? It seems you found the answer you were looking for and it helps the community when questions are not left without an accepted solution. Jul 16 '15 at 14:32
• Sure, but how? It's about 2 days as I'm registered here. Jul 16 '15 at 14:38
• æ has nothing to do with the Greek kappa. You might think they're similar, your readers won't. Jul 16 '15 at 14:42

You seem to be attaching meaning to a particular graphical representation of a symbol, but you shouldn't.

When hand writing, the variant kappa you seem to be discussing about often has two small loops, but typographical representations usually omit them. Those loops are probably responsible for you mistaking the symbol with the letter “æ” (used in Danish, Norwegian, Icelandic and Faroese and sometimes in English and French) that's a completely different thing.

You may not like the symbol \varkappa as provided by the amssymb package, but anyway you have to stick with some symbol you are able to reproduce and that's a realization of what Unicode calls GREEK KAPPA SYMBOL U+03F0.

Using æ for this is simply wrong.

You can get a “looping” realization within the Solomos font provided by the Greek Font Society and included in TeX Live (possibly also in MiKTeX).

\documentclass{article}
\usepackage{amsmath}
\usepackage{amssymb}

\DeclareFontFamily{U}{solomos}{}
\DeclareErrorFont{U}{solomos}{m}{n}{10}
\DeclareFontShape{U}{solomos}{m}{n}{
<-> s*[1.1]  gsolomos8r
}{}

\newcommand{\vkappa}{\text{\usefont{U}{solomos}{m}{n}\symbol{'153}}}

\begin{document}

A kappa $\kappa$ and its variant $\vkappa$.

This is different from \ae{} and should not be confused with it.

The symbol $\varkappa$ is just a graphic variant, there's
no meaning implied in the graphical appearance.

\huge $\vkappa$

\end{document}


• Yeah, I seem to call wrong the letter. Okay, how to put without any troubles \ae in formulas? Jul 16 '15 at 16:29
• @MGMKLML I've never seen “æ” used in formulas. Jul 16 '15 at 16:31
• A very fine answer, apart from one tiny point of pedantry. AFAIK æ isn't really a French letter. It gets used in Latin and Greek borrowings, but then it did in English too. And still does, very occasionally. Encyclopædia Britannica being the go-to example :P Jul 16 '15 at 16:32
• @Au101 Fixed, thanks for being pedant! :-) Jul 16 '15 at 16:36
• As far as I know the letter \ae is used in Phonetics too, especially for Medieval or Old English, but I've never seen it as a variable name
– user31729
Jul 16 '15 at 16:58

You could use renewcommand to redefine the kappa function if you'd like. The following code should do it:

\renewcommand\kappa{\text{\ae}}


Include this at the top of your file and all kappa calls should show the ae symbol. Notice that I have also wrapped ae in a text command, so that you won't get any warnings about being in a math environment. Typically warnings like this are nothing to worry about, but I understand it's nice to make them go away.

• I don't think that redefining a rather prominent symbol like \kappa is very useful
– user31729
Jul 16 '15 at 14:18
• @ChristianHupfer Nor do I, but it seems to be what OP is asking for... Jul 16 '15 at 14:24
• I've decided to define a new command called \Kappa, using your idea. Thank you a lot. Jul 16 '15 at 14:26
• You'll get different results when the context is upright and italic; for instance, in the statement of a theorem (usually typeset in italics), you'll get an italic æ whereas in normal text you'll get an upright æ. Jul 16 '15 at 15:43
• How to get everywhere what I need? Jul 16 '15 at 16:29