When the left-right parenthesis is too big, how to make it smaller?

When the left-right parenthesis is too big as in the example below, how do you make the parenthesis smaller?

         \documentclass[reqno]{amsart}
\usepackage{amssymb}
\usepackage{mathrsfs}
\usepackage{amsmath}
\usepackage{amsthm}
\usepackage{stackrel}
\usepackage{courier}
\usepackage[all,cmtip]{xy}
\usepackage{mathtools}
\usepackage{hyperref}
\usepackage{multicol}
\usepackage{enumerate}
\usepackage{bookmark}

\begin{document}

$\left( \bordermatrix{ & & \cr &a_{11} & a_{12} \cr &a_{21} & a_{22} \cr }, \bordermatrix{ & & \cr &b_{11} & b_{12} \cr &b_{21} & b_{22} \cr } \right)$

\end{document}


The command \small doesn't seem to work; I am getting errors. I would like the outer parenthesis to be the same size as the parenthesis around the matrices.

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Instead of \left and \right, you can use manual sizing commands. See here en.wikibooks.org/wiki/LaTeX/Mathematics#Manual_sizing BTW, welcome to tex.SX; it is customary here to post so called minimal working examples (MWEs) which are complete, compilable documents demonstrating your issue. – Christian Feb 23 '14 at 16:33
Welcome to TeX.SE! Please edit your posting to create a compilable MWE (minimum working example, starting with \documentclass and ending with \end{document}) that generates the problem behavior you're looking to address. In particular, please be sure to indicate which package(s) you load that provide the \bordermatrix macro; there are several packages that provide just such a macro, and it's important to know which one you're using. – Mico Feb 23 '14 at 16:35
@Christian Thank you. I have provided minimum working example. – user46728 Feb 23 '14 at 16:39
@Mico I have provided minimum working example. I probably added far more packages than you really need, but here it is. I hope this is helpful. – user46728 Feb 23 '14 at 16:40
@user46728 Yep, so it's not a minimum working example, technically. But this is definitely more helpful than the fragment you originally posted and the great number of useful answers you got probably speak to this :) – Christian Feb 23 '14 at 19:09

If you use the tabular or the matrix environment for your matrices, the \left and \right should always have the correct size.

\documentclass[reqno]{amsart}

\begin{document}

$\left( \left( \begin{tabular}{ll}$a_{11}$&$a_{12}$\\$a_{21}$&$a_{22}$\\ \end{tabular} \right) , \left( \begin{tabular}{ll}$b_{11}$&$b_{12}$\\$b_{21}$&$b_{22}$\\ \end{tabular} \right) \right)$

$\left( \left( \begin{matrix} a_{11} & a_{12} \\ a_{21} & a_{22} \\ \end{matrix} \right) , \left( \begin{matrix} b_{11} & b_{12} \\ b_{21} & b_{22} \\ \end{matrix} \right) \right)$

\end{document}

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Thank you Maarten! This worked perfectly! I will choose this as the accepted answer. – user46728 Feb 23 '14 at 17:03

\bordermatrix is a plain tex structure, and the fact that it is intended to incorporate an extra row at the top is what is forcing the outer parentheses to be much too large.

instead, you can use one of the amsmath "fenced" matrices. \pmatrix is what is recommended here:

\documentclass[reqno]{amsart}

\begin{document}
$\Biggl( \begin{pmatrix} a_{11} & a_{12} \\ a_{21} & a_{22} \end{pmatrix} . \begin{pmatrix} b_{11} & b_{12} \\ b_{21} & b_{22} \end{pmatrix} \Biggr)$

\end{document}


instead of \left and \right -- which in this case give outer parentheses the same size as the inner ones, i've used \Bigg ones, which are just slightly larger.

you're already using amsart, so you don't need to load amsmath. (amsart also incorporates amsthm, so you don't need that either, although it isn't relevant for this examples.)

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\bordermatrix is intended to place additional annotations in the "border" of a matrix. The empty line is seen by \left and \right and the size of the delimiters is increases. Package amsmath (loaded in your preamble) provides several matrix environments, pmatrix which can be used here to set a simple matrix with parentheses:

\documentclass[reqno]{amsart}
\usepackage{amsmath}

\begin{document}
$\left( \begin{pmatrix} a_{11} & a_{12} \\ a_{21} & a_{22} \end{pmatrix}, \begin{pmatrix} b_{11} & b_{12} \\ b_{21} & b_{22} \end{pmatrix} \right)$
\end{document}


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Here's one of many ways:

  \documentclass[reqno]{amsart}
\usepackage{tabstackengine}
\begin{document}
\setstacktabbedgap{2ex}
$\left( \parenMatrixstack{ a_{11} & a_{12} \\ a_{21} & a_{22} }, \parenMatrixstack{ b_{11} & b_{12} \\ b_{21} & b_{22} } \right)$
\end{document}


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Thank you! This works perfectly as well! – user46728 Feb 23 '14 at 17:09