Typesetting New Functions in LaTeX

latextypesetting

So, I just have a little question:

What is the "best way" to typeset new functions in LaTeX which aren't already included in the various packages? Right now I'm just using \mbox as my go-to method, but I just was wondering if there was a more "acceptable way of doing it (as with mbox, I have to make sure to include spaces around the text of the functions in order for it to not look too strange)

Here is an example:

$y(t)=2e^{1/2}\sqrt{\pi}\mbox{Erfi }(t)$

which comes out looking like:

$y(t)=2e^{1/2}\sqrt{\pi}\mbox{Erfi }(t)$ http://adamnbowen.com/images/error_function.jpg

Don't get me wrong… I think it looks fine, but I was just looking for some opinions (as far as best practices go).

Best Answer

\DeclareMathOperator (or, if you're using some weird distribution of LaTeX that doesn't have the AMS packages, \mathop{\mathrm{Erfi}})

See the always-useful UK TeX FAQ, specifically Defining a new log-like function in LaTeX.