General ⇒ big cartesian product

[Hornisse]

Hey everybody!
I want to illustrate a big cartesian product of sets. Is there a big version of the \times symbol for which indexes can be used? I don't want to use the \prod symbol, because in my math lectures we always use the cross symbol. Can somebody help me?
Hornisse

[Stefan Kottwitz]

Hi Hornisse,

welcome to the board!
The ifsym package provides the symbols \Cross, \BigCross and \Smallcross, perhaps they would be useful for you.

Stefan

[Hornisse]

Hey Stefan,
Thank you for your quick answer! Obviously I'm not an expert using LaTeX... Can you tell me how to download the ifsym package, respectively where I have to safe it? I tried it in the font folder, but it didn't work. The cross symbols you mentioned seem to be exactly what I need.
Hornisse

[Stefan Kottwitz]

Hi Hornisse,

which LaTeX distribution do you use? Some distributions like MiKTeX and TeX Live offer a package management tool for the installation, so you don't need to install it manually.
Btw. now I'm away for some time and can give other answers in about 2 hours, but perhaps other users would provide additional help.

Stefan

[Hornisse]

Hey!
I've just found out, that the package ifsym has already been installed. I checked it in the MikTex Package Manager. I also load the package in the pramble by \usepackage {ifsym}. Nevertheless the commands \Cross and \BigCross don't work.
Do you have any idea why?
Hornisse

[Stefan Kottwitz]

Just set the geometry option according to the documentation:

Code: Select all

\usepackage[geometry]{ifsym}

Stefan

[Hornisse]

Hey!
At last I've been able to use the ifsym package. Unfortunately, as the symbols are geometric ones, I can't use them as mathematical ones, i.e. I can't add indexes exactly below und over the symbol. Any other ides where to get such a cross symbol? I thought that this should be a standard symbol... Crosses within a circle are actually used to indicate product-sigma-algebras. I definately need one without circle

Hornisse

[localghost]

Perhaps you will find an appropriate symbol in "The Comprehensive LaTeX Symbol List". It lists nearly 5000 symbols and may contain what you are searching for.


Best regards
Thorsten¹

[brunosalcedo]

This is my first post, so please forgive me if I don't follow standard conventions.

I don't like using symbols from other packages because they modify the standard AMS symbols.
An alternative is to define the command yourself and then use it as needed.

I use the standard \times command, and simply declare it to be a math-operator so that you can have the proper superscripts and subscripts.

Code: Select all

\DeclareMathOperator*{\cart}{\times}

Example 1: $X = \cart_{i\in I} X_i$\\

Example 2: $X = \displaystyle\cart_{i\in I} X_i$\\

Example 3:
\begin{equation*}
X = \cart_{i\in I} X_i
\end{equation*}