# [texhax] Odd behavior in a \mathop

Mon Nov 3 17:42:26 CET 2008

On Mon, 3 Nov 2008, Michael Barr wrote:

> If you compile the file
> \documentclass{article}
> \newcommand\II{\mathop{I\mkern-1mu I}}
> \newcommand\I{\mathop{I}}
> \begin{document}
>
> $AB\II L$
>
> $AB\I L$
>
> \end{document}
>
> you will see (or I do anyway) that the I in the second, but not the first,
> formula is going distinctly below the line.  What is going on here?

If its argument is a single character, \mathop centers it
to with respect to the math-axis.

You can define

\newcommand\I{\mathop{\kern0pt I}

to avoid this.