I am using bold characters u,v,w,x in math mode. Is there a way to make a new command for that? Now I always have to type \bm{u}.
[Tex/LaTex] New command for bold characters in math mode
boldmath-mode
Related Solutions
I don't think you really wants this. However, here it is:
\documentclass{article}
\usepackage{amsmath}
\newcommand{\xnorm}[1]{%
\mathchoice{\Bigl\|#1\Bigr\|}{\lVert#1\rVert}{\lVert#1\rVert}{\lVert#1\rVert}%
}
\begin{document}
A norm in text mode is $\xnorm{v}$, while in display math it is
\[
\xnorm{v}=\sum_{i=1}^n\lvert v_i\rvert
\]
\end{document}
The result is really ugly (and wrong):
If you change \Bigl and \Bigr with \bigl and \bigr you get a more acceptable result, but I can't see the point of increasing the fences' size.
The following method only works in pdflatex. I use a pdf special to embolden the font, calling it \mathbbf[]{}. The optional argument allows an optional embolding factor to be specified (default 0.2).
In the MWE, the top line is \mathbbf, the next \mathbf, and the final is \textrm.
\documentclass[english]{scrartcl}
\usepackage[T1]{fontenc}
\usepackage[latin9]{inputenc}
\usepackage{textcomp}
\usepackage{amstext}
\usepackage{babel}
%%%%%
\usepackage{scalerel,lmodern}
\input pdf-trans
\newbox\qbox
\def\usecolor#1{\csname\string\color@#1\endcsname\space}
\newcommand\outline[1]{\leavevmode%
\def\maltext{#1}%
\setbox\qbox=\hbox{\maltext}%
\boxgs{Q q 2 Tr \thickness\space w 0 0 0 rg 0 G}{}%
\copy\qbox%
}
\newcommand\mathbbf[2][.2]{%
\def\thickness{#1}%
\ThisStyle{\outline{$\mathbf{\SavedStyle#2}$}}%
}
%%%%%
\begin{document}
$\mathbbf{x\text{\textasteriskcentered}}=\mathbbf{x}-\mathbbf{X}_{1}(\mathbbf{X}_{1}'\mathbbf{X}_{1})^{-1}\mathbbf{X}_{1}\mathbbf{x}$
$\mathbf{x\text{\textasteriskcentered}}=\mathbf{x}-\mathbf{X}_{1}(\mathbf{X}_{1}'\mathbf{X}_{1})^{-1}\mathbf{X}_{1}\mathbf{x}$
$\textrm{x\text{\textasteriskcentered}}=\textrm{x}-\textrm{X}_{1}(\textrm{X}_{1}'\textrm{X}_{1})^{-1}\textrm{X}_{1}\textrm{x}$
\end{document}
Best Answer
You can go
then use
\buinstead of\bm{u}this is a bit quicker than using\bmevery time as it only has to work out the corresponding bold font once. (That wouldn't be the case if you used\newcommand\bu{\bm{u}}which would expand to doing\bmevery tine.