symbols
\~, it will give you a tilde as an accent over the following letter.) I believe \backslash may be used in math formulae, but not into text itself. Lamport's, Kopka's, and Mittelbach's texts have said as much (but no more), and so left me hanging on how to get a backslash into regular text.
Here's a new implementation of \widebar, based on \overline. It works by hacking into amsmath's accent placement, so it needs that package. Here's a comparison of \widebar (first line) and \overline (second line):
I think the placement of the bars in the first line is better, except for the \sin z, where there's no difference. Note that \widebar works well together with superscripts, but not necessarily with subscripts. (\overline has the same issue.) It also works well over combined symbols like AB in most cases.
\documentclass{article}
\usepackage{amsmath}
\makeatletter
\let\save@mathaccent\mathaccent
\newcommand*\if@single[3]{%
\setbox0\hbox{${\mathaccent"0362{#1}}^H$}%
\setbox2\hbox{${\mathaccent"0362{\kern0pt#1}}^H$}%
\ifdim\ht0=\ht2 #3\else #2\fi
}
%The bar will be moved to the right by a half of \macc@kerna, which is computed by amsmath:
\newcommand*\rel@kern[1]{\kern#1\dimexpr\macc@kerna}
%If there's a superscript following the bar, then no negative kern may follow the bar;
%an additional {} makes sure that the superscript is high enough in this case:
\newcommand*\widebar[1]{\@ifnextchar^{{\wide@bar{#1}{0}}}{\wide@bar{#1}{1}}}
%Use a separate algorithm for single symbols:
\newcommand*\wide@bar[2]{\if@single{#1}{\wide@bar@{#1}{#2}{1}}{\wide@bar@{#1}{#2}{2}}}
\newcommand*\wide@bar@[3]{%
\begingroup
\def\mathaccent##1##2{%
%Enable nesting of accents:
\let\mathaccent\save@mathaccent
%If there's more than a single symbol, use the first character instead (see below):
\if#32 \let\macc@nucleus\first@char \fi
%Determine the italic correction:
\setbox\z@\hbox{$\macc@style{\macc@nucleus}_{}$}%
\setbox\tw@\hbox{$\macc@style{\macc@nucleus}{}_{}$}%
\dimen@\wd\tw@
\advance\dimen@-\wd\z@
%Now \dimen@ is the italic correction of the symbol.
\divide\dimen@ 3
\@tempdima\wd\tw@
\advance\@tempdima-\scriptspace
%Now \@tempdima is the width of the symbol.
\divide\@tempdima 10
\advance\dimen@-\@tempdima
%Now \dimen@ = (italic correction / 3) - (Breite / 10)
\ifdim\dimen@>\z@ \dimen@0pt\fi
%The bar will be shortened in the case \dimen@<0 !
\rel@kern{0.6}\kern-\dimen@
\if#31
\overline{\rel@kern{-0.6}\kern\dimen@\macc@nucleus\rel@kern{0.4}\kern\dimen@}%
\advance\dimen@0.4\dimexpr\macc@kerna
%Place the combined final kern (-\dimen@) if it is >0 or if a superscript follows:
\let\final@kern#2%
\ifdim\dimen@<\z@ \let\final@kern1\fi
\if\final@kern1 \kern-\dimen@\fi
\else
\overline{\rel@kern{-0.6}\kern\dimen@#1}%
\fi
}%
\macc@depth\@ne
\let\math@bgroup\@empty \let\math@egroup\macc@set@skewchar
\mathsurround\z@ \frozen@everymath{\mathgroup\macc@group\relax}%
\macc@set@skewchar\relax
\let\mathaccentV\macc@nested@a
%The following initialises \macc@kerna and calls \mathaccent:
\if#31
\macc@nested@a\relax111{#1}%
\else
%If the argument consists of more than one symbol, and if the first token is
%a letter, use that letter for the computations:
\def\gobble@till@marker##1\endmarker{}%
\futurelet\first@char\gobble@till@marker#1\endmarker
\ifcat\noexpand\first@char A\else
\def\first@char{}%
\fi
\macc@nested@a\relax111{\first@char}%
\fi
\endgroup
}
\makeatother
\newcommand\test[1]{%
$#1{M}$ $#1{A}$ $#1{g}$ $#1{\beta}$ $#1{\mathcal A}^q$
$#1{AB}^\sigma$ $#1{H}^C$ $#1{\sin z}$ $#1{W}_n$}
\begin{document}
\test\widebar
\test\overline
\end{document}
Here is my previous simpler implementation; the intended use is for single symbols. It also works when applied to several symbols, but then the placement of the bar may not be appropriate (see AW at the end). Moreover, subsequent superscripts may be placed too close to the bar.
\documentclass{article}
\usepackage{amsmath}
\makeatletter
\newcommand*\rel@kern[1]{\kern#1\dimexpr\macc@kerna}
\newcommand*\widebar[1]{%
\begingroup
\def\mathaccent##1##2{%
\rel@kern{0.8}%
\overline{\rel@kern{-0.8}\macc@nucleus\rel@kern{0.2}}%
\rel@kern{-0.2}%
}%
\macc@depth\@ne
\let\math@bgroup\@empty \let\math@egroup\macc@set@skewchar
\mathsurround\z@ \frozen@everymath{\mathgroup\macc@group\relax}%
\macc@set@skewchar\relax
\let\mathaccentV\macc@nested@a
\macc@nested@a\relax111{#1}%
\endgroup
}
\makeatother
\begin{document}
$\widebar{M}$ $\widebar{A}$ $\widebar{\mathcal A}$ $\widebar{g}$ $\widebar{\beta}$
$\widebar{AB}$ $\widebar{AW}$
$\overline{M}$ $\overline{A}$ $\overline{\mathcal A}$ $\overline{g}$ $\overline{\beta}$
$\overline{AB}$ $\overline{AW}$
\end{document}
In comments you indicated that it is the height of the ~ that is your concern, perhaps one of these does what you want:
\documentclass{article}
\begin{document}
a\textasciitilde b\raisebox{-1ex}{\textasciitilde}c\raisebox{-1.2ex}{\textasciitilde}d\raisebox{-2ex}{\textasciitilde}e
\end{document}
Best Answer
TL;DR
\textbackslashproduces a backslash in text-mode. The math-mode$\sim$and\texttildelow(fromtextcomppackage) are options for a lower tilde (while\~{}and\textasciitildeproduce a raised tilde in text-mode)Long Answer:
The Comprehensive LaTeX Symbol List is your friend. The correct link seems to keep changing, but if you have a complete TeX Live installation, the command
texdoc symbols-a4will display your local copy.\textbackslashand\textasciitildeare found in several places in the document, but the LaTeX 2e ASCII Table (Table 529 as of this writing) and the following discussion are a convenient resource for all ASCII characters. In particular, the discussion notes that\~{}and\textasciitildeproduce a raised tilde, whilst the math-mode$\sim$and\texttildeloware options for a lower tilde; the latter is in thetextcomppackage, and looks best in fonts other than Computer Modern. If you are typesetting file names or urls, the document recommends theurlpackage.Remember to delimit TeX macros from surrounding text, e.g.
bar\textasciitilde{}foo.