Ho can I declare a math operator which will appear in bold font?
I tried the following, but it didn't work:
\DeclareMathOperator{\Div}{Div}
\newcommand{\Divxk}{\mathbf{\Div}_{X/k}}
[Tex/LaTex] DeclareMathOperator in bold
math-modemath-operators
Related Solutions
unicode-math does most of its work at \begin{document}, so you have to delay your declarations too:
\documentclass{scrartcl}
\usepackage{amsmath}
\usepackage{unicode-math}
\setmathfont{TeX Gyre Pagella Math}
\newcommand{\diff}{\mathop{}\!\mathrm{d}} % better than using \,\mathrm{d}
\AtBeginDocument{
\let\div\relax
\DeclareMathOperator{\div}{div}
}
\begin{document}
\[
\int_V \div \vec{F} \diff V = \oint_A \vec{F} \cdot \vec{n} \diff A
\]
\end{document}
Note that this is only needed because you want to override a command defined by unicode-math. Using \DeclareMathOperator{\Div}{div} wouldn't need special precautions.
Try
\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\DeclareMathOperator{\op}{op}
\DeclareMathOperator{\opp}{\mathsf{op}}
\begin{document}
\noindent
\[a \op_k b\]
\noindent
\[a \opp_k b\]
\end{document}
Works fine here.
Best Answer
The
\mathbfaround\Divdoes nothing, because\Divis translated internally to something like "choose the\mathrmfont and typeset ‘Div’”. Math fonts don't inherit features from the context:\mathrmalways corresponds to the upright text font in medium weight (or boldface) if\boldmathis in force.You can check that
produces a medium weight ‘x’.
So you have to define
The definition of
\Divbecomes “choose the\mathrmfont and typeset ‘\mathbf{Div}’”, so, for the same reason as before, the boldface font will be chosen.