如何排版“\utimes”（类似于 \uplus）

Question

在数学模式下，排版类似于\uplus（不相交集合并集的符号，由嵌入在并集符号内的加号组成）的符号的最简单方法是什么，仅用“乘号”符号代替加号？

Answer 1

\uplus似乎具有状态mathbin，而\biguplus似乎具有状态mathop。以下\utimes和的定义\bigutimes保留了这些设置。

\documentclass{article}
\usepackage{amsmath} %for "\boldsymbol" macro

\newcommand\utimes{\mathbin{\ooalign{$\cup$\cr%
   \hfil\raise0.42ex\hbox{$\scriptscriptstyle\times$}\hfil\cr}}}
\newcommand\bigutimes{\mathop{\ooalign{$\bigcup$\cr%
   \hfil\raise0.36ex\hbox{$\scriptscriptstyle\boldsymbol{\times}$}\hfil\cr}}}

\begin{document}
$a\uplus a$  $a\biguplus a$

$a\utimes a$ $a\bigutimes a$

$\uplus\utimes$

${\biguplus}{\bigutimes}$
\end{document}

参数\raise0.42ex 和 0.36ex 分别被选择用于使\uplus和\utimes布局尽可能相似，以适应 Computer Modern 数学字体系列——这是大多数 TeX 发行版中的默认字体系列（包括上面显示的屏幕截图）。对于其他数学字体系列，\raise可能必须考虑 的其他参数。

Answer 2

适应\times很\cup麻烦；在这里我使用picture模式来添加符号。

\documentclass{article}
\usepackage{amsmath,pict2e}

\makeatletter
\DeclareRobustCommand{\utimes}{\mathbin{\mathpalette\u@times\relax}}
\newcommand\u@times[2]{%
  \begingroup
  \ifx#1\displaystyle\@tempswatrue\else
    \ifx#1\textstyle\@tempswatrue\else
      \@tempswafalse
  \fi\fi
  \sbox\z@{$\m@th#1{\cup}$}%
  \setlength{\unitlength}{\wd\z@}%
  \begin{picture}(0,0)
  \roundcap
  \linethickness{\variable@rule{#1}}
  \put(0,0){\box\z@}
  \if@tempswa
    \Line(0.3,0.25)(0.7,0.65)
    \Line(0.7,0.25)(0.3,0.65)
  \else
    \Line(0.3,0.2)(0.7,0.6)
    \Line(0.3,0.6)(0.7,0.2)
  \fi
  \end{picture}%
  \phantom{\cup}%
  \endgroup
}
\DeclareRobustCommand{\bigutimes}{\DOTSB\mathop{\mathpalette\bigu@times\relax}\slimits@}
\newcommand{\bigu@times}[2]{%
  \begingroup
  \sbox\z@{$\m@th#1{\bigcup}$}%
  \setlength{\unitlength}{\wd\z@}%
  \begin{picture}(0,0)
  \roundcap
  \ifx#1\displaystyle
    \linethickness{2\variable@rule{#1}}
  \else
    \linethickness{1.5\variable@rule{#1}}
  \fi
  \put(0,0){\box\z@}
  \ifx#1\displaystyle
    \Line(0.25,0.0)(0.75,0.5)
    \Line(0.25,0.5)(0.75,0.0)
  \else
    \Line(0.3,0.1)(0.7,0.5)
    \Line(0.3,0.5)(0.7,0.1)
  \fi
  \end{picture}%
  \phantom{\bigcup}%
  \endgroup
}
\newcommand{\variable@rule}[1]{%
  \fontdimen8  
  \ifx#1\displaystyle\textfont3\else
    \ifx#1\textstyle\textfont3\else
      \ifx#1\scriptstyle\scriptfont3\else
        \scriptscriptfont3\relax
  \fi\fi\fi
}
\makeatother

\begin{document}

$a\uplus b\utimes c_{\uplus\utimes}$

$\displaystyle\biguplus\bigutimes
 \textstyle\biguplus\bigutimes
 \scriptstyle\biguplus\bigutimes$

$\displaystyle\biguplus_{i=1}^n\bigutimes_{i=1}^n$

\end{document}

Answer 3

常规字体\cup太窄，无法容纳\times字符，因此我选择了替代字体。使用正确的字距调整后，该符号也\bigcup可用于“等”。\scriptstyle

因为它应该是一个操作员，所以\DeclareMathOperator似乎是一个正确的选择。

\documentclass{article}

\usepackage{amsmath}

\DeclareMathOperator{\utimes}{\bigcup\utimeskern\times}
\newcommand{\utimeskern}{%
  \mkern-17.5mu
  \mathchoice{}{}{\mkern0.2mu}{\mkern0.5mu}%
}

\begin{document}

See $\utimes A$


\end{document}

Answer 4

根据我的回答将两个符号组合成一个完全可扩展的符号，我提供\cuptimes和\bigcuptimes。

\documentclass[a4paper,10pt]{article}
\usepackage{stackengine,scalerel}
\newcommand{\bigcuptimes}{\mathop{\ThisStyle{%
  \ensurestackMath{\stackinset{c}{0pt}{c}{.25\LMex}{\times}{\SavedStyle\bigcup}}}}}
\newcommand{\cuptimes}{\mathop{\ThisStyle{%
  \ensurestackMath{\stackinset{c}{.3\LMpt}{c}{0\LMpt}{\SavedStyle^\times}{\SavedStyle\cup}}}}}
\begin{document}
$\displaystyle\bigcup_{i\in I}S_i$\hspace{40pt}    
$\bigcup_{i\in I}S_i$\hspace{40pt}
$S_1\cup S_2$
    \vspace{20pt}

$\displaystyle\bigcuptimes_{i\in I}S_i$\hspace{40pt}
$\bigcuptimes_{i\in I}S_i$\hspace{40pt}
$S_1\cuptimes S_2$
    \vspace{20pt}

$\scriptstyle\bigcuptimes_{i\in I}S_i$\hspace{40pt}
$\scriptscriptstyle\bigcuptimes_{i\in I}S_i$
    \vspace{20pt}

$\scriptstyle S_1\cuptimes S_2$\hspace{40pt}
$\scriptscriptstyle S_1\cuptimes S_2$
\end{document}