# Sup-left with a matrix

If I want to have supscript on the left, I usually do {}^xa. How can I do this when I have a matrix. So what I want is

{}^x\begin{pmatrix} a & b \\ c & d\end{pmatrix}

However, this doesn't raise the x high enough.

I just need this for one application.

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If you are not using it that often you can match the size of the delimiter height and kern it slightly via {\vphantom{\bigg(}}^x\!\!\begin{pmatrix} a & b \\ c & d\end{pmatrix} –  percusse Jun 17 '14 at 5:09
@percusse: Great. Thanks. I just need to do this one time, so this works well. If you write it as an answer, I will upvote and accept. –  Thomas Jun 17 '14 at 5:12

Package mathtools (an extension package to amsmath) provides \prescript:

\prescript{<left superscript>}{<left subscript>}{<arg>}


Full example:

\documentclass{article}
\usepackage{mathtools}
\begin{document}
$\prescript{x}{}{\begin{pmatrix} a & b \\ c & d\end{pmatrix}}$
\end{document}


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In case you need it more frequently, the tensor package should solve the problem of height.

\documentclass{article}

\usepackage{amsmath}
\usepackage{tensor}

\begin{document}

$\tensor*[^x]{\begin{pmatrix} a & b \\ c & d\end{pmatrix}}{}$

\end{document}


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Here's an option using stacks. Because it is a lap, one may (or not) wish to add horizontal space prior to the \tllap.

\documentclass{article}
\usepackage{stackengine,mathtools}
\stackMath
\begin{document}
$\tllap{\scriptstyle x} {\begin{pmatrix} a & b \\ c & d\end{pmatrix}}$
\end{document}


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