[Tex/LaTex] Digit zero with a dot inside also in text mode

empheqequationsnumbering

\documentclass[a4paper,11pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage{empheq}

\makeatletter
\newcommand*{\pmzerodot}{%
\nfss@text{%
\sbox0{$\vcenter{}$}% math axis
\sbox2{0}%
\sbox4{0\/}%
\ooalign{%
  0\cr
  \hidewidth
  \kern\dimexpr\wd4-\wd2\relax % compensate for slanted fonts
  \raise\dimexpr(\ht2-\dp2)/2-\ht0\relax\hbox{%
    \if b\expandafter\@car\f@series\@nil\relax
      \mathversion{bold}%
    \fi
    $\cdot\m@th$%
  }%
  \hidewidth
  \cr
  \vphantom{0}% correct depth of final symbol
}%
}%
}
\makeatother

\begin{document}
\begin{empheq}{align}
0 + 1 = 1
\end{empheq}
\end{document}

enter image description here

How to add \pmzerodot in equation number?

Best Answer

The following example defines \dotarabic, which similar to \arabic prints the arabic form of a counter with the zeros exchanged by \pmzerodot. \theequation is redefined to use \dotarabic instead of \arabic (or \arabic can be redefined, if the zero with dot should be used by all counter outputs).

Furthermore \pmzerodot is made robust, because \the<counter> are subject to the \label/\ref system. Fragile commands will break during the definition of the internal \@currentlabel.

Full example:

\documentclass[a4paper,11pt]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{lmodern}
\usepackage{empheq}

\makeatletter
\DeclareRobustCommand*{\pmzerodot}{%
  \nfss@text{%
    \sbox0{$\vcenter{}$}% math axis
    \sbox2{0}%
    \sbox4{0\/}%
    \ooalign{%
      0\cr
      \hidewidth
      \kern\dimexpr\wd4-\wd2\relax % compensate for slanted fonts
      \raise\dimexpr(\ht2-\dp2)/2-\ht0\relax\hbox{%
        \if b\expandafter\@car\f@series\@nil\relax
          \mathversion{bold}%
        \fi
        $\cdot\m@th$%
      }%
      \hidewidth
      \cr
      \vphantom{0}% correct depth of final symbol
    }%
  }%
}

\newcommand*{\dotarabic}[1]{%
  \expandafter\@dotarabic\csname c@#1\endcsname
}
\newcommand*{\@dotarabic}[1]{%
  \expandafter\dotarabic@scan\number #1\relax
}
\newcommand*{\dotarabic@scan}[1]{%
  \ifx\relax#1%
    \expandafter\@gobble
  \else
    \expandafter\@firstofone
  \fi
  {%
    \ifnum#1=0 %
      \ifincsname
        0%
      \else
        \pmzerodot
      \fi
    \else
      #1%
    \fi
    \dotarabic@scan
  }%
}
\makeatother

\renewcommand*{\theequation}{\dotarabic{equation}}

\begin{document}
  \addtocounter{equation}{9}
  \begin{empheq}{align}
    \label{eq:test}
    \pmzerodot + 1 = 1
  \end{empheq}
\end{document}

Related Solutions

[Tex/LaTex] Text mode commands/symbols in math mode

You can define your own symbol:

\documentclass{article}
\usepackage{amsmath}

\DeclareMathSymbol{\subfactorial}{\mathord}{operators}{"3C}

\begin{document}
\begin{equation}
\begin{aligned}
n!=\sum_k h(n,k) &= \sum_k \binom{n}{k}(n-k)\subfactorial\\
  &=\sum_k\binom{n}{k}k\subfactorial
\end{aligned}
\tag{5.49}
\end{equation}
\end{document}

This will work so long as the "operators" font is OT1 encoded. Should it be T1 encoded, change "3C" into "BD (this might depend on your font settings).

The equation (same number) is taken from "Discrete Mathematics", by Graham, Knuth and Patashnik (the original uses Euler fonts, but the result is quite similar).

enter image description here

[Tex/LaTex] How to label text with equation number

Here's one way (taken some code from Input manually a number into \eqref):

enter image description here

\documentclass{article}
\usepackage{amsmath}% http://ctan.org/pkg/
\makeatletter
\newcommand{\eqnum}{\refstepcounter{equation}\textup{\tagform@{\theequation}}}
\makeatother
\begin{document}
\begin{equation}
  f(x) = ax^2 + bx + c \label{myeqn1}
\end{equation}
See~\eqref{myeqn1}. Also
\begin{itemize}
  \item $A$ is very~$b$, \eqnum\label{myeqn2}
  \item $A$ is not~$c$. \eqnum\label{myeqn3}
\end{itemize}
There is also~\eqref{myeqn2} and~\eqref{myeqn3}.
\end{document}

The above MWE provides \eqnum which inserts the equation number using the amsmath \eqref way. A subsequent \label makes one able to reference it. Of course, the print-and\label technique could be combined, if needed:

\makeatletter
\newcommand{\eqlab}[1]{\refstepcounter{equation}\label{#1}\textup{\tagform@{\theequation}}}
\makeatother

which allows one to use \eqlab{<label>}.

For flushed-right equation numbering, use the following definition:

\newcommand{\eqnum}{\leavevmode\hfill\refstepcounter{equation}\textup{\tagform@{\theequation}}}

Best Answer

Related Solutions

[Tex/LaTex] Text mode commands/symbols in math mode

[Tex/LaTex] How to label text with equation number

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