How to resize a fomula inside a block?

Question

I would like to insert a formula as a block in my presentation:

\begin{block}{concretization}{
$\renewcommand{\arraystretch}{1.5}%
  \begin{array}{l}
  \gamma \rightarrow ...
  \end{array}$
}\end{block}

The formula is a little bit too large... So should I resize it or change the whole font size of the presentation? Is it possible to let Beamer decide the factor of scaling?

Another question is... is it normal that I add $ in the beginning and the end of array, otherwise it gives me an error...

Answer 1

Scaling the font or resizing an entire block of text to make things fit is usually not a good idea from a typesetting point of view, since it introduces inconsistencies for the end-user (reader in this case). Fiddling with the spacing is a more viable option, since the font size is left untouched. However, this may be a moot point if your equation (or whatever) is "a little bit too large". Perhaps then, resizing things will not be as noticeable to the viewer/reader.

If you want an absolute resizing, then \resizebox{<hlen>}{<vlen>}{<stuff>} from the graphicx package would work:

\documentclass{beamer}
\usepackage{graphicx}% http://ctan.org/pkg/graphicx
\begin{document}
\begin{frame}
...
\begin{block}{concretization}
  \renewcommand{\arraystretch}{1.5}%
  \resizebox{!}{5mm}{% Height of 5mm; maintain aspect ratio
    $\begin{array}{l}
      p_1(x)=a_0+a_1x+a_2x^2 \\
      p_2(x)=b_0+b_1x+b_2x^2+b_3x^3 \\
      p_3(x)=c_0+c_1x+c_2x^2+c_3c^3+c_4x^4
    \end{array}$%
  }
\end{block}
...
\end{frame}
\end{document}

If you want a relative resizing, then \scalebox{<factor>}{<stuff>} would work:

\documentclass{beamer}
\usepackage{graphicx}% http://ctan.org/pkg/graphicx
\begin{document}
\begin{frame}
...
\begin{block}{concretization}
  \renewcommand{\arraystretch}{1.5}%
  \scalebox{0.5}{% Scale by 50%
    $\begin{array}{l}
      p_1(x)=a_0+a_1x+a_2x^2 \\
      p_2(x)=b_0+b_1x+b_2x^2+b_3x^3 \\
      p_3(x)=c_0+c_1x+c_2x^2+c_3c^3+c_4x^4
    \end{array}$%
  }
\end{block}
...
\end{frame}
\end{document}
​

In the above examples, the resizing and scaling have been exaggerated to illustrate the effects.