Unsqueeze the fraction

Question

For the LaTeX code below,

 \begin{equation}
Fitness(\CS)=
\begin{cases}
    0.5 + 0.5 \cdot G(\CS)                        & if\ V(\CS)=0 \\
    0.5\cdot G(\CS)-\frac{V(\CS)}{V_{Tot}(\CS)}   & otherwise.
\end{cases}~\label{eq:fitness}
\end{equation}

I get the output

It looks like the fraction \frac{V(\CS)}{V_{Tot}(\CS)} is a bit squeezed here,I would prefer

which looks less squeezed. How could I do that?

Answer 1

mathtools defined dcases which puts the entries inside in display math mode. This causes fractions and other mode-varying elements to conform to their largest size:

\documentclass{article}
% mathtools also loads amsmath (http://ctan.org/pkg/amsmath)
\usepackage{mathtools}% http://ctan.org/pkg/mathtools
\newcommand{\CS}{CS}
\DeclareMathOperator{\Fitness}{Fitness}
\begin{document}

% Original cases
\begin{equation}
  Fitness(\CS)=
  \begin{cases}
    0.5 + 0.5 \cdot G(\CS)                        & if\ V(\CS)=0 \\
    0.5\cdot G(\CS)-\frac{V(\CS)}{V_{Tot}(\CS)}   & otherwise.
  \end{cases}\label{eq:fitness1}
\end{equation}

% Updated dcases, operator definition and text
\begin{equation}
  \Fitness(\CS)=
  \begin{dcases}
    0.5 + 0.5 \cdot G(\CS)                        & \text{if\ }V(\CS)=0 \\
    0.5\cdot G(\CS)-\frac{V(\CS)}{V_{\text{Tot}}(\CS)}   & \text{otherwise.}
  \end{dcases}\label{eq:fitness2}
\end{equation}

\end{document}

Textual elements are forced as text using \text, while an operator like Fitness should also be declared as such. See the amsmath documentation for more on these topics.