[Tex/LaTex] eliminate space between tilde and letter in equations

equationsmath-modespacing

New bye here, I have a situation to solve, with two different behaviors of the tilde. The first looks normal, within a regular text, something like:

... some text $\sim$A then some text ...

but in equation mode (or even inside the equation dollar signs within the text), there is a space between the tilde and the letter (see the screenshot below):

... some text $\sim{A}$ then some text ...

Is there a way to eliminate that space, in equation mode?

I need it for equations mode:

\[ \sim{A} = ... \]

If relevant, in the preamble I use the package lmodern to use the CM10 font., plus some others dealing with equations: mathptmx, amssymb, amsmath, mathspec and parse the text with xelatex.

Best Answer

The default "math type" of \sim is mathrel, i.e., that of a relational operator. (Another example of an operator of type mathrel is =.) The default math type of the letter A is mathord ("math ordinary"). As you've "discovered", TeX automatically inserts some whitespace -- in the amount of \thickmuskip -- between elements of types mathrel and mathord, respectively.

If you do not wish to get whitespace between \sim and A, simply write

{\sim}A

This setup changes the math type of \sim to mathord, and TeX does not insert extra whitespace between elements of type mathord.

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[Tex/LaTex] widetext equation in revtex4 messed up

I had a similar issue with a widetext environment overlapping an equation environment, I solve it using \begin{align}...\end{align} instead of \begin{equation}...\end{equation} for the overlapped equation, in your case try

\begin{align}
E(b)&=\int\limits_{-\infty}^{\infty}\varphi_2^*(x)\left(-\frac{1}{2}\frac{d^2}{dx^2}+x^{2p}\right)\varphi_2(x)\ dx=\\
&=\frac{2b^3}{\pi}\int\limits_{-\infty}^{\infty}\left\{\frac{1}{x^2+b^2}\left[-\frac{1}{2}\left(-\frac{2 \left(b^2-3x^2\right)}{\left(b^2+x^2\right)^3}\right)\right.\right.+\\
&+\left.\left.\frac{x^{2p}}{x^2+b^2}\right]\right\}=\\
&=\frac{1}{4b^2}+(-1)^p\frac{b^{2p}}{2}(1-2p)
\label{eq:Eb2}
\end{align}

[Tex/LaTex] Math mode spacing (or glyph bounds) with mathspec

Lierre: Thanks for posting a complete MWE. Good news: I can reproduce your problems. Better news: On my system at least, they go away entirely when I omit the "(Latin,Digits)" option. Why do you specify these options, incidentally?

Addendum, 18/20 Sept 2011: I've just found out about the latest release of the XITS math (and text) fonts; see the XITS site for the five .otf files. The XITS Math letters have much better, i.e., larger sidebearings. If XITS and XITS Math are sufficiently Times-like for your needs, I think you'll be very pleased. The new MWE would look something like

% !TeX program = xelatex
\documentclass{article}
\usepackage{unicode-math}
\setmainfont{XITS}
\setmathfont{XITS Math}
\begin{document}
\noindent
$e^j + |f|$ \\
$abcdefghijklmnopqrstuvwxyz$ XITS-Math math italics\\    
\textit{abcdefghijklmnopqrstuvwxyz} XITS text italics\\    
\setmainfont{Times New Roman}
\textit{abcdefghijklmnopqrstuvwxyz} TNR text italics
\end{document}

enter image description here

I guess the right-hand sidebearing of the f in the first line could still be a bit more generous, but it's a huge improvement over the example with TNR that you posted originally!

Comparing the italics letters of the XITS Math font with the (text) italics letters of Times New Roman, the main new characteristics of the new math font seem to be:

very different shapes of v and w
larger "teardrop" terminals of the letters f and r
the letter z has a rudimentary "swash" (but it's nowhere near as pronounced as the swash of the italic z in either Computer Modern or MathtimePro (the latter with the zswash option set)
most letters are a bit more condensed and their vertical strokes are a bit thicker

Second Addendum, 27 May 2017: Recently, the STIX fonts project has released version 2.0 of the Stix Fonts. The STIX Two Text and STIX Two Math fonts may be obtained for free from https://sourceforge.net/projects/stixfonts/. The STIX Two Math (and Text) fonts represent a major step forward relative to the XITS and orginal Stix fonts. To wit, the math kerning is much improved in the following screenshot relative to what would be provided by XITS Math (see the screenshot above). The STIX Two italic glyphs -- in both text and math mode -- are also less slanted (or: more upright) than their Stix, XITS, and Times New Roman counterparts.

% !TeX program = lualatex
\documentclass{article}
\usepackage{unicode-math}
\setmainfont{STIX Two Text}
\setmathfont{STIX Two Math}
\begin{document}
\obeylines % just for this example
$e^j + |f|$ 
$abcdefghijklmnopqrstuvwxyz$ --- STIX Two Math, math italics   
\textit{abcdefghijklmnopqrstuvwxyz} --- STIX Two Text, text italics

\setmainfont{XITS}[Scale=MatchLowercase] % make sure x-heights match
\emph{abcdefghijklmnopqrstuvwxyz} --- XITS Text, text italics
\end{document}

Best Answer

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