How to prevent upper case in page header?

Question

I just came across this small problem which I can't seem to fix. I have a section which looks like this:

\section{Properties of $C_q$}

The problem is that the header of the page uses upper case and so it displays this section title as if I had written

\section{Properties of $C_Q$}

How can I make sure the q is always lower case?

Answer 1

You could define a macro for this expression:

\newcommand{\Cq}{C_q}

and protect it when you use it in such headings:

\section{Properties of $\protect\Cq$}

\protect prevents early expansion of the macro, this way also becoming uppercase is prevented. You may use this macro later in your math expression as well, of course, that's why I did not start math mode inside the macro.

Btw. I would not use all caps headers. In case of fancyhdr, for example, uppercasing can be disabled by \nouppercase, such as

\rhead{\nouppercase\leftmark}