[Tex/LaTex] \mathbbm in exponent of equation

equationssymbols

I am trying to put a blackboard 1 (indicator function; I'm using the bbm package) in the exponent of an equation, something like

\begin{align*}
  f(x) = \mathbbm{1}(x = 1) \\  % works
  p(x) = q^{\mathbbm{1}(x = 1)} % does not work
\end{align*}

I've also tried putting in a \protect before \mathbbm, to no avail. The error is

dfTeX error: /usr/local/texlive/bin/i386-linux/pdflatex (file bbm8): Font bbm8 at 600 not found

EDIT: As several kind commenters have pointed out, this code compiles in isolation. I have determined that the source of problem is likely something in my style file since changing the document class to book works just fine.
Any pointers of what to look for in the .cls file?

Best Answer

Load the bbm package.

\documentclass{article}
\usepackage{bbm}
\begin{document}
\[p(x) = q^{\mathbbm{1}(x = 1)}\]
\end{document}

output

Related Solutions

[Tex/LaTex] How would one have an equation for an exponent

Just to give a little closure...

Depends on what you want. As egreg said, you can go by

$2^{(n-1)/3}$

...or you could also try using \frac{numerator}{denominator}, as in

$2^{\frac{n-1}{3}}$

[Tex/LaTex] Unusual symbol in equation

I guess the main issues are, how to create a large open square symbol, center it on the math axis, and have it act as a math operator, i.e., place its argument below (and above, if there's an upper limit) the large open square. Sort of like \sum, right? A series of \vcenter, \hbox, and repeated \mathlarger instructions applied to the \Box macro solve these issues. (If you compare the following screenshot with the preceding one, you'll notice that the letter g to the left of the box is placed ever so slightly higher now.)

\documentclass{article}
\usepackage{amsmath,  % for "\DeclareMathOperator*" macro
            amsfonts, % for "\Box" macro
            relsize}  % for "\mathlarger" macro
\newcommand{\BigBox}{\vcenter{\hbox{$\mathlarger{\mathlarger 
     {\mathlarger{\mathlarger{\mathlarger{\Box}}}}}$}}}
\DeclareMathOperator*{\bigsquare}{\BigBox}

\begin{document}
\[
Z_{\mathcal{T}/G}\equiv \sum_{h\in G}\frac{1}{|G|} 
     \sum_{g\in G} g {\bigsquare_{\textstyle h}}
\]
\end{document}

Addendum -- Another way to create \BigBox is to load the graphicx package and to run

\newcommand{\BigBox}{\vcenter{\hbox{\scalebox{2}{$\Box$}}}}

As you've indicated in a comment that \BigBox isn't an "operator" but a partition function with boundary conditions, I think it makes sense -- from a LaTeX point of view -- to define a macro called, say \partfunc, that takes two arguments, here: g and h, and to align the first argument on the math axis.

\documentclass{article}
\usepackage{amsmath,  % for "\DeclareMathOperator*" macro
            amsfonts, % for "\Box" macro
            graphicx} % for "\scalebox" macro
\newcommand\BigBox{\vcenter{\hbox{\scalebox{2}{$\Box$}}}}
\newcommand\bigsquare{\mathop{\BigBox}\limits}
\newcommand\partfunc[2]{\vcenter{\hbox{$\textstyle #1$}}{\bigsquare_{\textstyle #2}}}

\begin{document}
\[
Z_{\mathcal{T}/G}\equiv \sum_{h\in G}\frac{1}{|G|} 
     \sum_{g\in G} \partfunc{g}{h}
\]
\end{document}

Best Answer

Related Solutions

[Tex/LaTex] How would one have an equation for an exponent

[Tex/LaTex] Unusual symbol in equation

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