[Tex/LaTex] how to print long relation operators like simeq and sim with text above in latex

math-modemath-operatorsstacking-symbols

ENV

xelatex --version
XeTeX 3.14159265-2.6-0.99991 (TeX Live 2014)
bibtex --version
BibTeX 0.99d (TeX Live 2014)

\mathrel{\simeq\!\simeq} not what I want.
\stackrel{\text{mytext}{\simeq}} the operator not long.

Any idea? Thanks.

Best Answer

Based on my answer at Big tilde in math mode, in introduce \reallywidesim and \reallywidesimeq.

\documentclass{article}
\usepackage{scalerel}
\usepackage{stackengine,amsmath}
\newcommand\reallywidesimeq[1]{\mathrel{\ThisStyle{%
  \setbox0=\hbox{$\SavedStyle\mkern2mu_{\text{#1}}\mkern2mu$}%
  \mkern1mu\stackengine{1\LMpt}{%
    \stretchto{\scaleto{\SavedStyle\mkern-1mu\simeq\mkern-1mu}{.72\wd0}}{1\ht0}%
  }{$\SavedStyle_{\text{#1}}$}{O}{c}{F}{T}{S}\mkern1mu%
}}}
\newcommand\reallywidesim[1]{\mathrel{\ThisStyle{%
  \setbox0=\hbox{$\SavedStyle\mkern3mu_{\text{#1}}\mkern3mu$}%
  \mkern1mu\stackengine{1\LMpt}{%
    \stretchto{\scaleto{\SavedStyle\mkern-1mu\sim\mkern-1mu}{.54\wd0}}{1\ht0}%
  }{$\SavedStyle_{\text{#1}}$}{O}{c}{F}{T}{S}\mkern1mu%
}}}
\def\testeq#1{$%
  \reallywidesimeq{#1}\,
  \scriptstyle\reallywidesimeq{#1}\,
  \scriptscriptstyle\reallywidesimeq{#1}
$\par}
\def\test#1{$%
  \reallywidesim{#1}\,
  \scriptstyle\reallywidesim{#1}\,
  \scriptscriptstyle\reallywidesim{#1}
$}
\parskip 1ex
\begin{document}
\test{abcdefghijklm}\quad\testeq{ab}
\test{abcdefghijk}\quad\testeq{abc}
\test{abcdefghi}\quad\testeq{abcde}
\test{abcdefg}\quad\testeq{abcdefg}
\test{abcde}\quad\testeq{abcdefghi}
\test{abc}\quad\testeq{abcdefghijk}
\test{ab}\quad\testeq{abcdefghijklm}\par
$A \reallywidesim{mytext} B \reallywidesimeq{mytext} C$
\end{document}

Related Solutions

[Tex/LaTex] How to typeset an isomorphism symbol ($\simeq$) with a long bar

The following constructs the math symbol \isomorphism similar to \simeq, but with a longer line:

\documentclass{article}

\makeatletter
\newcommand*{\isomorphism}{%
  \mathrel{%
    \mathpalette\@isomorphism{}%
  }%
}
\newcommand*{\@isomorphism}[2]{%
  % Calculate the amount of moving \sim up as in \simeq
  \sbox0{$#1\simeq$}%
  \sbox2{$#1\sim$}%
  \dimen@=\ht0 %
  \advance\dimen@ by -\ht2 %
  %
  % Compose the two symbols
  \sbox0{%
    \lower1.9\dimen@\hbox{%
      $\m@th#1\relbar\isomorphism@joinrel\relbar$%
    }%
  }%
  \rlap{%
    \hbox to \wd0{%
      \hfill\raise\dimen@\hbox{$\m@th#1\sim$}\hfill
    }%
  }%
  \copy0 %
}
\newcommand*{\isomorphism@joinrel}{%
  \mathrel{%
    \mkern-3.4mu %
    \mkern-1mu %
    \nonscript\mkern1mu %
  }%
}
\makeatother

\begin{document}
\[ A \isomorphism B \simeq C = D \sim E \]
\[ A \isomorphism B^{C \isomorphism D^{E \isomorphism F}} \]
\end{document}

Remarks:

The line is constructed similar to \longrightarrow. There a line \relbar is joined a \rightarrow. The joining removes the side bearings, which means the glyphs can have white margins at the left and the right. LaTeX's \joinrel adds a negative space of 3mu to move the relational symbols together. The test file uses the symbol in smaller math styles, there -3mu leaves a gap, therefore \isomorphism@joinrel is defined with customized settings (-3.4mu for \displaystyle and \textstyle, -4.4mu for scriptstyle and \scriptscriptstyle).
The symbol \sim is horizontally centered and set in the same math style and size. It is raised to the same height as aymbol \simeq.
The vertical position of the line in \simeq is unhappily not available in TeX, therefore a guessed value is used (the shift of \sim multiplied by 1.9). If you want the line a little higher, then you can decrease the factor.
\mathpalette is used to support the symbol in all math styles. Then the internal macro \@isomorphism gets the math style (\displaystyle, \textstyle, \scriptstyle, \scriptscriptstyle) as first argument. The second argument is not used and left empty.
The measuring and glyph composing is done with many low level plain TeX macros for efficiency (and fun).
\m@th sets \mathsurround to 0pt. Usually the value is 0pt, but if set, then the space that should surround math expressions should not occur inside a formula or math symbol.

[Tex/LaTex] Equivalence of sequence: \sim with some text under

If you want an operator to respect \limits you should use \DeclareMathOperator*. However, this is the wrong tool for the required symbol, because it would make an operator rather than a relation symbol, with wrong spacing. Then

\newcommand{\isEquivTo}[1]{\underset{#1}{\sim}}

seems better for your needs. Note that \underset will “know” that \sim is a relation symbol, so it will use the right spacing around it.

\documentclass{article}
\usepackage{amsmath}

\newcommand{\isEquivTo}[1]{\underset{#1}{\sim}}

\begin{document}
\[
\sin(n) + n \isEquivTo{+\infty} n
\]

\end{document}

On the other hand, setting the subscript under the symbol won't give good results when inline; here's a better definition that uses \underset only in display style. Look carefully at the output to see why it's better not using the \underset form for inline formulas.

\documentclass{article}
\usepackage{amsmath}

\newcommand{\isEquivTo}[1]{%
  \mathpalette\isEquivToInner{#1}%
}
\newcommand{\isEquivToInner}[2]{%
  \ifx#1\displaystyle
    \underset{#2}{\sim}
  \else
    \sim_{#2}
  \fi
}

\begin{document}
some text some text some text some text some text some text some text some text
some text some text some text some text some text some text some text some text
$\displaystyle\sin(n) + n \isEquivTo{+\infty} n$
some text some text some text some text some text some text some text
some text some text some text some text some text some text some text
$\sin(n) + n \isEquivTo{+\infty} n$
some text some text some text some text some text some text some text
some text some text some text some text some text some text some text
\[
\sin(n) + n \isEquivTo{+\infty} n
\]
\end{document}

If you want a syntax like \isEquivTo_{+\infty}, you can do it with xparse:

\documentclass{article}
\usepackage{amsmath}
\usepackage{xparse}

\NewDocumentCommand{\isEquivTo}{e{_}}{\isEquivToA#1}
\NewDocumentCommand{\isEquivToA}{m}{%
  \IfNoValueTF{#1}
    {\sim}
    {\mathpalette\isEquivToB{#1}}%
}
\newcommand{\isEquivToB}[2]{%
  \ifx#1\displaystyle
    \underset{#2}{\sim}
  \else
    \sim_{#2}
  \fi
}

\begin{document}
Here is the command without subscript $n \isEquivTo n$

some text some text some text some text some text some text some text some text
some text some text some text some text some text some text some text some text
$\displaystyle\sin(n) + n \isEquivTo_{+\infty} n$
some text some text some text some text some text some text some text 
some text some text some text some text some text some text some text 
$\sin(n) + n \isEquivTo_{+\infty} n$
some text some text some text some text some text some text some text 
some text some text some text some text some text some text some text 
\[
\sin(n) + n \isEquivTo_{+\infty} n
\]
\end{document}

You will see that the first call just does \sim.

ENV

Best Answer

Related Solutions

[Tex/LaTex] How to typeset an isomorphism symbol ($\simeq$) with a long bar

[Tex/LaTex] Equivalence of sequence: \sim with some text under

Related Question