sublabel parenthesis changed to mathmode using subfig.sty

Question

My code follows:

\documentclass{book}
\usepackage{graphicx}
\usepackage{subfig}%
\captionsetup[subfloat]{%
font=normalsize,labelformat=parens,labelsep=space}


\begin{document}

\begin{figure}
\subfloat[\label{fig:eBoxEndowment}]{\includegraphics[width=0.47\columnwidth]{10821_001_fig_001a.pdf}}\hfill
\subfloat[\label{fig:eBoxPrices}]{\includegraphics[width=0.47\columnwidth]{10821_001_fig_001b.pdf}}
\caption{The Edgeworth box. The axes along which the endowment and
}
\end{figure}

\end{document}

I got the output as:

How can I change the sublabel parenthesis into mathmode, i.e., (a) should come as $($a$)$,... Please suggest

Answer 1

A solution using the subcaption package:

\documentclass{book}
\usepackage{graphicx}
\usepackage{caption}
\usepackage[font+=normalsize,labelformat=simple,labelsep=space]{subcaption}
\renewcommand\thesubfigure{$($\alph{subfigure}$)$}

\begin{document}

\begin{figure}
    \begin{subfigure}[b]{.45\linewidth}
        \includegraphics[width=\textwidth]{example-image}
        \caption{}
        \label{fig:eBoxEndowment}
    \end{subfigure}
    \hfill
    \begin{subfigure}[b]{.45\linewidth}
        \includegraphics[width=\textwidth]{example-image}
        \caption{}
        \label{fig:eBoxPrices}
    \end{subfigure} 
    \caption{The Edgeworth box. The axes along which the endowment and}
\end{figure}

\end{document}