10

I know \Cap (or \doublecap) and I know \bigcap. However, now I also need \bigCap (or \bigdoublecap) which is a \bigcap with another \cap in between.

I already tried using \stackinset from the stackengine package, but was not able to produce decent results.

3
  • 1
    Do you just want these symbols overlaid?
    – Werner
    Oct 17, 2013 at 22:48
  • I could live with that solution, although a smaller \cap would make it better to read.
    – C-Otto
    Oct 17, 2013 at 22:54
  • i believe this was added to unicode. check the stix fonts. Oct 18, 2013 at 2:45

2 Answers 2

8

Not pretty, but if nothing else comes along, maybe you can do with this.

\documentclass{article}
\usepackage{amsmath,graphicx}
\newcommand{\bigdoublecap}{%
  \mathop{\vphantom{\bigcap}\vcenter{\hbox{\text{%
    \ooalign{$\displaystyle\bigcap$\cr
             \hidewidth
             \raisebox{-.1ex}{\resizebox{.7\width}{.875\height}{$\displaystyle\bigcap$}}%
             \hidewidth\cr
    }%
  }}}}%
}

\begin{document}
\[
\bigdoublecap_{i=1}^n A_i
\]
\end{document}

enter image description here

3
  • Looks very pretty to me :)
    – C-Otto
    Oct 17, 2013 at 22:57
  • 2
    @C-Otto Note that a % was missing and I added it.
    – egreg
    Oct 17, 2013 at 22:58
  • Noted, thanks. And say hi to Fausto Spoto from me :)
    – C-Otto
    Oct 17, 2013 at 23:24
6

I used \stackinset AND routines from the scalerel package. What it insets is a \bigcap that has been scaled down to 1.6ex in height (which narrows it to the proper width), and then vertically stretched to 2ex in height. The manipulated inset is placed, horizontally centered, .15pt above the base of the unaltered \bigcap.

\documentclass{article}
\usepackage{amsmath}
\usepackage{scalerel}
\usepackage{stackengine}[2013-10-15]
\newcommand\bigdoublecap{%
  \mathop{\ensurestackMath{\stackinset{c}{}{b}{.15pt}%
    {\stretchto{\scaleto{\bigcap}{1.6ex}}{2ex}}{\bigcap}}}
}
\begin{document} 
\[
\bigdoublecap_{i=1}^n A_i
\]\end{document}

enter image description here

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