Matrix notation in ClassicThesis

In Classic Thesis Style Guide, the author suggests to not use bold fonts. For vectors an alternative is arrow \vec. If I don't want to use \mathbold, what is the best alternative to mark matrix in your opinion?

-
Isn't there a well-established standard in your field? What do the books and papers that you read do? –  Federico Poloni Nov 12 '12 at 19:47
I believe the suggestion not to use bold applies for running text where bold destroys the uniform (grey) colour of the text. For regular equations, there is not really any argument not to use bold. One might try to argue about inline equations, but even there, math naturally changes the colour, so using bold should not be much or a problem (you might even argue that you want inline equations to stand out a little more). What about just restricting the use of uppercase letters for matrices in your equations? –  mforbes Nov 12 '12 at 20:13
In my field matrices are bold, definitely. There is lot of them, and they are in many places, also in text. So, if I use bold in regular equation, there also will be some bold in text. Actually, restriction of using uppercase letters only for matrices is good... simple and good. Thank you! I need to review my set of variables. –  Johny Nov 12 '12 at 20:30

If bold is out of the question, I might use a script style capital:

\documentclass{article}
\usepackage{amsfonts}
\usepackage{mathtools}

\newcommand\mat[1]{\mathcal{#1}}

\begin{document}
$\mat{A}=\begin{bmatrix}1&2\\3&4\end{bmatrix}$

\end{document}

-
Thank you for answer, it's good idea, perfect if one have a few matrices. But for me, script capital seems to be little bit too "fancy->hard to read" in equations with many matrices. Personally, I think, bold is good choice, but... I'm not "style-specialist"... –  Johny Nov 12 '12 at 19:44
Fair enough. You'll want to distinguish matrices in some way so that either means that you will need to use a slightly different font, or that you'll need some sort of decoration. I personally prefer not to use decorations, but \vec{A} also works. In any case, you'll want to define a macro (as in my edit) so that if you change your mind at some point, it's not a disaster. –  Scott H. Nov 12 '12 at 20:03
For now, macro seems to be, the best idea. Thank you, again! But I will still looking for some other solution. –  Johny Nov 12 '12 at 20:26

I find that in handwritten texts I have seen, matrices are commonly written uppercase and underlined. I would say this may be a good option in computer-written texts as well, depending on your preferences. So e.g. you could have:

% Preamble
\newcommand{\mat}[1]{\underline{#1}}
% In your document where you want the matrix, and a vector for comparison
\mat{M} \vec{v}


And the result could look like:

$\underline{A} \vec{v}$

-

You should take something which is recognized by your readers. Following the standards is more important than some typographic rule. If you have to change this, you should describe it clearly in your symbols list. And in every case, use a macro for it in order to be able to change it later on.

If you just need it very few time, you could use one of the two last versions in my MWE. I cite the ISO here, as it is a good standard to stick to, I guess:

% arara: pdflatex

\documentclass{article}
\usepackage{csquotes}
\usepackage{mathtools}
\usepackage{bm} % for version a
\newcommand{\matrva}[1]{\bm{#1}} % recomended by ISO
\newcommand{\matrvb}[1]{\mathsf{#1}} % you can also take any other font. See Scott's answer. Just describe that in your symbols list
\newcommand{\matrvc}[1]{(\MakeLowercase{#1}_{ij})}
\newcommand{\matrvd}[1]{[\MakeLowercase{#1}_{ij}]}

\begin{document}
From DIN~EN~ISO~8000-2:2013-08:

\enquote{Usually, matrices are written as bold/slanted upper-case letters [...]; other fonts, however, may be equally used.}

The example given here is $\matrva{A}$. An other possibility would be to use the definition of the matrix which is $\matrva{A}\coloneqq\matrvc{A}$ or equally the squared version $\matrvd{A}$.
\end{document}


-