# Draw a box around each element of the xy-pic

How could I draw lines (like those in a tabular environment drawn by \hline and |c|c|c| in the following code?

\resizebox{\textwidth}{!}{
\xymatrix{
x_0 \ar[dr]    & x_1 \ar[d] \ar[dr] & x_2 \ar[d]   \\
%
\sum(x_0..x_0) & \sum(x_0..x_1)     & \sum(x_1..x_2)\\
}
}


For some reason, I can't compile the document if I use *F{argument} in order to draw a box around each element.

To make more clear who ideally the output would be:

\begin{tabular}{| c| c| c|}
\hline
x_0& x_1& x_2\\ \hline
\end{tabular}


followed by the arrows.

-

Please provide a minimal example. You have to use the syntax: *+[F]{<argument>}

\documentclass{article}
\usepackage{graphicx}
\usepackage{xypic,xypdf}
\begin{document}
\noindent\resizebox{\textwidth}{!}{
\xymatrix{
*+[F]{x_0} \ar[dr]    & x_1 \ar[d] \ar[dr] & x_2 \ar[d]   \\
%
\sum(x_0..x_0) & \sum(x_0..x_1)     & \sum(x_1..x_2)\\
}
}
\end{document}


You can set the frame global:

\documentclass{article}
\usepackage{graphicx}
\usepackage{xypic,xypdf}
\begin{document}
\noindent\resizebox{\textwidth}{!}{
\entrymodifiers={++[F]}
\xymatrix{
x_0 \ar[dr]    & x_1 \ar[d] \ar[dr] & x_2 \ar[d]   \\
%
\sum(x_0..x_0) & \sum(x_0..x_1)     & \sum(x_1..x_2)\\
}
}
\end{document}


-