X-like symbol for Cartesian Product (Blyth)

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Discussion Overview

The discussion centers around the representation of the Cartesian Product using a symbol similar to a capital X, as referenced in T. S. Blyth's book on Module Theory. Participants explore the use of LaTeX and MathJax to create this symbol, discussing potential commands and limitations.

Discussion Character

  • Technical explanation
  • Exploratory

Main Points Raised

  • Peter inquires about the LaTeX code for a large 'times' symbol resembling a capital X for the Cartesian Product.
  • Some participants suggest that the normal AMS package may not support this symbol, noting that while \bigotimes works in Mathjax, \bigtimes does not.
  • Jameson mentions experimenting with \bigtimes but finds no solution, expressing disappointment over the limitations.
  • Another participant proposes a workaround using MathJax, providing a custom command to create a large sansserif capital X, but ultimately suggests that the standard product symbol \prod may be preferable.

Areas of Agreement / Disagreement

Participants express uncertainty about the availability of a suitable symbol in standard LaTeX packages, with no consensus on a definitive solution. Some agree on the limitations of existing commands, while others propose alternative approaches.

Contextual Notes

The discussion highlights limitations in LaTeX and MathJax regarding the representation of the Cartesian Product symbol, with participants relying on custom commands and expressing varying degrees of success.

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In T. S. Blyth's book on Module Theory, the author uses a large 'times' symbol (similar to a capital X) for the Cartesian Product as seen in the text below (taken from Blyth page 58)
View attachment 3458Can someone help me with the Latex code for such a symbol?Peter
 
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Hmm, I've been reading up on this for a little bit now and it might be that this isn't possible with the normal AMS package.

There is a \bigotimes command that works with Mathjax but \bigtimes doesn't.

$$\bigotimes$$

Here is a SE post about this topic. Maybe someone else can find a solution. :)
 
Jameson said:
Hmm, I've been reading up on this for a little bit now and it might be that this isn't possible with the normal AMS package.

There is a \bigotimes command that works with Mathjax but \bigtimes doesn't.

$$\bigotimes$$

Here is a SE post about this topic. Maybe someone else can find a solution. :)

Thanks Jameson ... yes, I experimented with \bigtimes as well ...

Pity that there appears to be no solution to this ...

Peter
 
Using MathJax, the best I can do is $$\mathop{\vcenter{\huge\times}}_{i=1}^n x_i$$. If you are using a complete implementation of LaTeX, I found a useful post here showing how to use a Maltese cross as a large operator symbol. I adapted that to use with a large sansserif capital X, and I found that this works very well. The code
Code:
\documentclass{article}
\begin{document}
\newcommand{\xprod}{%
  \mathop{ %
    \mathchoice{\dobigx\huge}
               {\dobigx\Large}
               {\dobigx\normalsize}
               {\dobigx\small}
    }
}
\newcommand{\dobigx}[1]{%
  \vcenter{\kern.2ex\hbox{\sffamily#1X}\kern.2ex}}
Here it is in text, with the usual product symbol for comparison: $\xprod_{i=1}^n x_i$, $\prod_{i=1}^n x_i$. In display style, it looks like
\[
\xprod_{i=1}^n x_i \qquad \prod_{i=1}^n x_i
\]
\end{document}
produced this output:

View attachment 3465

In practice, I think it is much better to stick with the usual product symbol $$\prod.$$
 

Attachments

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    xprod.png
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