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%%  Ein Beispiel der DANTE-Edition
%%  Mathematiksatz mit LaTeX
%%  3. Auflage
%%  Beispiel 10-05-1 auf Seite 221.
%%  Copyright (C) 2018 Herbert Voss
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\usepackage{eucal,amsmath,esint}
\usepackage{lucida-otf}% Fonts von tug.org
\setmathfont{Lucida Bright Math OT}[range=\partial,math-style=upright]% Lualatex
\newcommand*\Q[2]{\frac{\partial#1}{\partial#2}} \newcommand*\diff{\mathop{}\!\symup{d}}
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\begin{document}
The \emph{first theorem of Green} is:
\[
  \underset{\mathcal{G}\quad}\iiint\!\left[u\nabla^{2}v+\left(\nabla u,
  \nabla v\right)\right]\diff^{3}V=\underset{\mathcal{S}\quad}\oiint u\Q{v}{n}\diff^{2}A
\]
The \emph{second theorem of Green} is:
\[
  \underset{{\mathcal{G}\quad}}\iiint\!\left[u\nabla^{2}v-v\nabla^{2}u\right]\diff^{3}V
    =\underset{\mathcal{S}\quad}\oiint\left(u\Q{v}{n}-v\Q{u}{n}\right)\diff^{2}A
\]
\end{document}