Reduce size \bigcup

I want to reduce size \bigcup_{n=1}^\infty? How can I do it?

I tried \newcommand*{\medcap}{\mathbin{\scalebox{0.75}{\ensuremath{\bigcap}}}

• Welcome to TeX.SE! Can you please make your code snippets compilable? – Mensch Oct 4 '17 at 22:21
• Welcome to TeX.SX! \scalebox{1}{...} doesn't change the size. – egreg Oct 4 '17 at 22:22
• it is rather unusual to change the size of individual characters, a font is designed as a coherent whole (ideally) so if neither \cup nor \bigcup are suitable perhaps you should be using a different font? – David Carlisle Oct 4 '17 at 22:24
• it would be easier to answer this question if you provided some context. is this being used in text? in display? please provide a small compilable example that we can experiment with. – barbara beeton Oct 4 '17 at 22:27
• Look: tex.stackexchange.com/questions/38709/is-there-a-medium-cap I want a "medium \cap (\cup)" with limits – Euler Oct 4 '17 at 22:28

You can probably simply use the smaller version available in the font:

\documentclass{article}

\usepackage{amsmath}

\begin{document}

zzz
$\bigcup_0^n > {\textstyle \bigcup\limits_0^n} > \mathop{\cup}_0^n$

\end{document}


with the example added in comments I would keep the standard bigcup but use more reasonable brackets

$\lambda\left(\bigcup_{j=1}^\infty E_k\right % no:-) > \lambda\Bigl(\bigcup_{j=1}^\infty E_k\Bigr)$


Maybe you want the symbol to have the same size in display style as in text style. The thread you link is for growing the symbol bigger.

The argument to \reduceoperator should be a comma separated list of names of operators.

\documentclass{article}
\usepackage{amsmath}
\usepackage{etoolbox}

\makeatletter
\newcommand{\reduceoperator}[1]{%
\@for\next:=#1\do{\expandafter\reduceoperator@\expandafter{\next}}%
}
\newcommand{\reduceoperator@}[1]{%
\csletcs{normal@#1@}{#1@}%
\csedef{#1@}{\noexpand\reduceoperator@@\csname normal@#1@\endcsname}%
}
\newcommand{\reduceoperator@@}[1]{%
\mathop{\mathpalette\reduceoperator@@@{#1}}%
}
\newcommand{\reduceoperator@@@}[2]{%
\ifx#1\displaystyle\textstyle\fi#2%
}
\makeatother

\reduceoperator{bigcup,bigcap,bigotimes}

\begin{document}

$\bigcup_{i=1}^m\bigcap_{j=1}^n A_{ij}\bigotimes_{k=1}^uB_k$
\begin{center}% to test inline math
$\bigcup_{i=1}^m\bigcap_{j=1}^n A_{ij}$
\end{center}

\end{document}


You can use the \medmath command from nccmath or \mathsmaller from relsize:

\documentclass[12pt]{article}
\usepackage[english]{babel}
\usepackage{mathtools, nccmath, relsize}

\begin{document}

$\bigcup_{n=1}^\infty A_n\qquad \medmath{\bigcup_{n=1}^\infty} A_n\qquad \mathsmaller{\bigcup\limits_{n=1}^\infty A_n}$

\end{document}