How can I represent the vectorization of a matrix A (i.e, vec(A))? I am talking about this simple operator:
[Tex/LaTex] Vectorization operator
formattingmath-mode
Related Solutions
The reason for the difference is that TeX typesets superscripts differently whether it follows a character or a box, as described in rule 18a of Appendix G of The TeXbook. As the macro \operatorname boxes its contents (because it calls \mathop which does), that's why \operatorname{A}^2 and \operatorname{A^2} differ (the first superscript concerns a box, whereas the second only the preceding A). You can easily see that an \operatorname and an \hbox behave similarly:
\documentclass{article}
\usepackage{graphicx}
\usepackage{amsmath}
\usepackage{xcolor}
\begin{document}
\begin{tabular}{ccc}
\scalebox{5}{$\operatorname{A}^2$} & \scalebox{5}{$\hbox{A}^2$} & \scalebox{5}{$\operatorname{A^2}$} \\
\verb"$\operatorname{A}^2$" & \verb"$\hbox{A}^2$" & \verb"$\operatorname{A^2}$" \\
\end{tabular}
\raisebox{1.22cm}[0pt]{\color{red}\rule{\textwidth}{0.4pt}}
\end{document}
Here are the technical details of the actual computations made by TeX in the present case:
\documentclass[a4paper]{article}
\usepackage{graphicx}
\usepackage{xcolor}
\usepackage{geometry}
\begin{document}
\setbox0=\hbox{$a$}% to initialize the maths fonts
\begingroup
\newdimen\h
\newdimen\q
\newdimen\boxedu
\newdimen\unboxedu
\newdimen\sigmafourteen
\newdimen\sigmafive
\q=\the\fontdimen18\scriptfont2
\sigmafourteen=\the\fontdimen14\textfont2
\sigmafive=\the\fontdimen5\textfont2
\def\tabularheading{\itshape\color{red!70!black}}
\noindent List of relevant font parameters and their values:
\begin{quote}
\begin{tabular}{lll}
\tabularheading Name & \tabularheading Symbol & \tabularheading Value \\
\texttt{x\_height} & $\sigma_5$ & \the\sigmafive \\
\texttt{sup2} & $\sigma_{14}$ & \the\sigmafourteen \\
\texttt{sup\_drop} & $q$ (it's $\sigma_{18}$ of superscript font) & \the\q \\
\end{tabular}
\end{quote}
Comparison of the amount the superscript is shifted up for a boxed and unboxed $A$:
\begin{quote}
\setbox0=\hbox{$A$}
\h=\the\ht0
\def\maxof#1#2{%
\ifdim#1>#2%
#1%
\else
#2%
\fi}
\begin{tabular}{lll}
& \tabularheading Boxed $A$ & \tabularheading Unboxed $A$ \\
\tabularheading height $h$ & \the\h & \the\h \\
\tabularheading base superscript shift $u_0$ & $h-q = \mathrm{\the\dimexpr\h-\q\relax}$ & 0pt \\
\tabularheading real shift $u = \max(u_0,\sigma_{14},\frac{1}{4}\sigma_5)$ &
\boxedu=\dimexpr\h-\q\relax
\boxedu=\maxof{\boxedu}{\sigmafourteen}%
\global\boxedu=\maxof{\boxedu}{.25\sigmafive}%
\the\boxedu
&
\unboxedu=0pt
\unboxedu=\maxof{\unboxedu}{\sigmafourteen}%
\global\unboxedu=\maxof{\unboxedu}{.25\sigmafive}%
\the\unboxedu
\end{tabular}
\end{quote}
Comparision of the calculations with the real typesetting:
\begin{quote}
\begin{tabular}{cc}
\scalebox{5}{$\hbox{$A$}^2$\hbox{$A$\raise\boxedu\hbox{$\scriptstyle2$}}} & \scalebox{5}{$A^2$\hbox{$A$\raise\unboxedu\hbox{$\scriptstyle2$}}} \\
\tabularheading boxed $A$ & \tabularheading unboxed $A$ \\
\end{tabular}
\raisebox{1.35cm}[0pt]{\color{blue}\rule{9.5cm}{0.4pt}}
\end{quote}
\endgroup
\end{document}
Just define a new command for it:
\newcommand{\ca}{{\sim}}
I suggest also to use siunitx, if you have units of measure to typeset in your document: it ensures uniform setting.
\documentclass{article}
\newcommand{\ca}{{\sim}}
\usepackage{siunitx}
\sisetup{input-protect-tokens=\ca,input-symbols=\ca}
\begin{document}
\SI{\ca 4}{eV}
$\ca 4$\,eV
\end{document}
The input might seem more difficult, but it's surely rewarding.
If you load amssymb you can change the definition to
\usepackage{amssymb}
\newcommand{\ca}{{\thicksim}}
and the result would be
Best Answer
If all you want is getting something like
then
\DeclareMathOperatoris the way to go:One has to choose a different name than
\vecor\Vecbecause these already have a meaning.