Definition_wave_equation_operator.tex

%
% Copyright © 2018 Peeter Joot.  All Rights Reserved.
% Licenced as described in the file LICENSE under the root directory of this GIT repository.
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\makedefinition{d'Alembertian (wave equation) operator.}{dfn:continuity:120}{
In this book, the symbol \( \dAlembertian \) is used to represent the \textit{d'Alembertian (wave equation) operator}, with a positive sign on the Laplacian term
\begin{equation*}
\dAlembertian =
\conjstgrad
\stgrad
=
\spacegrad^2 - \inv{c^2} \PDSq{t}{}.
\end{equation*}
} % definition