“supertabular” affects text that comes after the table finishes

After having searched on the internet for a few hours, I could finally make a longtable that spans over many, many pages. Besides, I was able to split this table into two columns (in order for my work to fill less pages). I was able to do this by using the supertabular package.

1. The problem is that the text in the next section, which comes after the table finishes, appears in one column instead of being displayed as usual.

2. Besides, there is too much space left before the table begins, and I want to get rid of that space. I tried the needspace package but it doesn't work.

CODE:

\documentclass{amsart}

\usepackage{supertabular}

\begin{document}

\centering{
\twocolumn
\tablehead{{$A$} & $B$ &          $C$ \\}
\begin{supertabular}{|c|c|c|}
\hline
{\bf a} &          b &  {\bf c} \\
\hline
{\bf a} &          b & {\bf c} \\
\end{supertabular}
}

\end{document}

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Welcome to TeX.SE. It would be helpful if you composed a fully compilable MWE including \documentclass and the appropriate packages that sets up the problem. While solving problems is fun, setting them up is not. Then those trying to help can simply cut and paste your MWE and get started on solving problem. –  Peter Grill Nov 2 '12 at 4:33

You have specified \twocolumn, hence the two columns. So you need to switch back to one column mode, and \onecolumn seems to do that just fine.

Notes:

• The \centering macro does not take any parameters. It should be used within a group.
• The additional spacing before and after is coming from the switching of the number of columns in the document.

Code:

\documentclass{amsart}

\usepackage{supertabular}
\usepackage{lipsum}

\begin{document}

{\centering
\twocolumn
\tablehead{{$A$} & $B$ &          $C$ \\}
\begin{supertabular}{|c|c|c|}
\hline
{\bf a} &          b &  {\bf c} \\
\hline
{\bf a} &          b & {\bf c} \\
\end{supertabular}
}
\onecolumn

\lipsum[1-4]
\end{document}

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I'd move \onecolumn past the closing brace –  egreg Nov 2 '12 at 9:29
@egreg: Done... –  Peter Grill Nov 2 '12 at 17:27