Emphasize the exponential function in the text

I want to typeset something like this:

[...] $y = \exp(x)$, where $\exp$ is the exponential function.


However, I don't like that $\exp$ is not at all emphasized in the text. What are good alternatives? Is leaving math mode a good idea?

[...] $y = \exp(x)$, where \textit{exp} is the exponential function.


Somehow, this does not seem very elegant.

I would not recommend changing the font style, I would rather add some redundant information, such as the definition of exp, or set it in quotes.

\documentclass{article}
\begin{document}
$y = \exp(x)$, where $\exp\colon x \mapsto \mathrm{e}^x$ is the
exponential function.

$y = \exp(x)$, where $\exp$'' is the exponential function.
\end{document}


I assume you want not only "exp", but all letter-based math operators to use a slanted/italic font shape instead of the basic upright/roman shape. It's straightforward to do so -- see the code below. (I owe the code to a comment by @HenriMenke -- thanks, Henri!)

By the way, I'm sure you'll get plenty of advice not to do change the font shape; however, since you asked...

\documentclass{article}
\makeatletter
\let\operator@font=\it
\makeatother

\begin{document}
$y = \exp(x)$, where $\exp$ is the exponential function.
\end{document}

• To get all operators in italics you could use \let\operator@font=\it. – Henri Menke Oct 12 '15 at 21:03
• @HenriMenke - Ah, a very good suggestion; I'll update my answer. – Mico Oct 12 '15 at 21:08

If you have a message then convey it with explicit intentions. Put explicitly

I use $\exp(\bullet)$ to denote the exponential function $e^\bullet$
to better typeset the argument without the superscript font size.


Don't hide it in the definition clauses if you really think this is a detail that might confuse people.