# Bold bracket row vector/matrix

I want to define a matrix-vector product, which is defined something like this:

\left[\begin{array}{cccc}
A & B & C & D
\end{array}\right]
\left[\begin{array}{c}
u \\ v \\ w \\ y
\end{array}\right] = 0.


So the matrix is actually a row vector of characters, which are matrices of course. As a result I get a row vector with thinner bracket size than the column vector. I tried bmatrix as an environment but it doesn't change anything and using \big[ just makes the brackets larger instead of bold.

Is there a common way to make beautiful row vectors with same bracket size as a column vector and which got nice spaces between the characters/numbers without using commas?

• Just to confirm you want a normal height bracket but with the stroke width of the stretched bracket on the column vector? Or do you want tall brackets around the row vector, the same as the column one? Jan 10, 2014 at 13:39
• yes, normal height Jan 10, 2014 at 13:40
• for normal height, but bolder, brackets, \usepackage{amsmath} and \boldsymbol[ / \boldsymbol] (or \lbrack and \rbrack). \boldsymbol and \left / \right don't work well together. Jan 10, 2014 at 13:49
• That's a pity as in general it's not really available, most fonts use thicker strokes on the larger brackets. You could try using \scalebox{1.5}{1}{(} to stretch a bracket horizontally but that distorts it really and doesn't really do the right thing or you can use bm package and \bm{(} which will use a bracket from the bold font which may or may not match the stretched bracket, depending on which fonts you are using Jan 10, 2014 at 13:50
• \boldsymbol[seems to me, that it is still thinner than the column bracket and with \lbrack i just get the normal size. Also the bm package is thinner. Jan 10, 2014 at 13:58

If using a Times Roman font instead of Computer Modern is an option for you, you may want to look into using the MathTime Professional II math font package to achieve your objective. Its square brackets are satisfyingly thick even at the smallest sizes.

Note that while the full MathTime Pro II package isn't free of charge, its "lite" subset, which is all that's needed in this case, is free of charge.

\documentclass{article}
\usepackage{amsmath}
\usepackage[lite]{mtpro2}
\begin{document}

$\begin{bmatrix} A & B & C & D \end{bmatrix} \begin{bmatrix} u \\ v \\ w \\ y \end{bmatrix} = 0.$

\end{document}
`