Math & Science ⇒ \dot inside \bigcup

[Lumy]

Hello,

exists \cup and \bigcup command that includes a dot centered in it? Not, MnSymbol package.

[phi]

Here is a method to fake this symbol when using the CM fonts:

Code: Select all

\documentclass{article}

\usepackage{etoolbox}

\makeatletter
\providerobustcmd*{\bigcupdot}{%
  \mathop{%
    \mathpalette\bigop@dot\bigcup
  }%
}
\newrobustcmd*{\bigop@dot}[2]{%
  \setbox0=\hbox{$\m@th#1#2$}%
  \vbox{%
    \lineskiplimit=\maxdimen
    \lineskip=-0.7\dimexpr\ht0+\dp0\relax
    \ialign{%
      \hfil##\hfil\cr
      $\m@th\cdot$\cr
      \box0\cr
    }%
  }%
}
\makeatother

\begin{document}

$a \bigcupdot a \bigcup a$

\[ \bigcupdot a \bigcup a \]

\[ T_{a \bigcupdot a \bigcup a} \]

\end{document}

[Lumy]

Thank you for your answer.