I want to use the double-bar notation for second-order tensors, which is common in continuum mechanics (e.g. for the strain and stress tensors).
I've searched the Comprehensive LATEX Symbol List but failed to find anything conclusive in there.
I've found this discussion, in which Stefan and Thorsten propose the alternatives below.
Is there a preferred way of typesetting this accent?
Subsidiary question: what is the difference between \bar
and \Bar
?
\documentclass{article}
\usepackage{amsmath}
\begin{document}
$\bar{\bar\tau} \quad
\Bar{\Bar\tau} \quad
\overline{\overline\tau}$
\end{document}
\show\Bar
gives\bar
so no difference (at least inamsmath
)amsmath.sty
has\def\Bar{\bar}
, so (as percusse said) there's no difference (inamsmath
).amsmath
, in order to get double accents one had to use the uppercase variant; this is no longer necessary fromamsmath
version 2. The old commands have been retained for backwards compatibility.