# Writing X as a symbol with limits

I wish to write X as product like $X_{n=1}^k$. How to write it? For example, we write $\sum \limits _{n=1}^k$

• Welcome to TeX.SX! I am not sure if I get you right. Please explain a bit more, what you want to achieve here. If necessary draw a little picture and post it. Do you want to get a new symbol which is used like \prod \limits but looks like a big X? – LaRiFaRi Sep 22 '14 at 11:09
• I wish to write \times but a bit larger with limits. – 6-0 Sep 22 '14 at 11:11
• Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. – Martin Schröder Sep 22 '14 at 11:19
• There are several related posts: tex.stackexchange.com/search?q=bigtimes – egreg Sep 22 '14 at 12:37

# Classical TeX

Both MnSymbol and mathabx provides the symbol \bigtimes. However both packages also change the math symbols, but it is also possible to only get \bigtimes.

## MnSymbol

\documentclass{article}
\usepackage{MnSymbol}

\begin{document}
$\bigtimes_{n=1}^k$
\end{document}


Version without package MnSymbol by using the relevant code from the package only:

\documentclass{article}

% MnSymbol

\usepackage{amsmath}% provides \DOTSB and \slimits@
\makeatletter
\DeclareFontFamily{U}  {MnSymbolF}{}
\DeclareSymbolFont{symbolsMN}{U}{MnSymbolF}{m}{n}
\SetSymbolFont{symbolsMN}{bold}{U}{MnSymbolF}{b}{n}
\DeclareFontShape{U}{MnSymbolF}{m}{n}{
<-6>  MnSymbolF5
<6-7>  MnSymbolF6
<7-8>  MnSymbolF7
<8-9>  MnSymbolF8
<9-10> MnSymbolF9
<10-12> MnSymbolF10
<12->   MnSymbolF12}{}
\DeclareFontShape{U}{MnSymbolF}{b}{n}{
<-6>  MnSymbolF-Bold5
<6-7>  MnSymbolF-Bold6
<7-8>  MnSymbolF-Bold7
<8-9>  MnSymbolF-Bold8
<9-10> MnSymbolF-Bold9
<10-12> MnSymbolF-Bold10
<12->   MnSymbolF-Bold12}{}
\DeclareMathSymbol{\tbigtimes}{\mathop}{symbolsMN}{2}
\newcommand*{\bigtimes}{%
\DOTSB
\tbigtimes
\slimits@
}
\makeatother

\begin{document}
$\bigtimes_{n=1}^k$
\end{document}


## mathabx

\documentclass{article}
\usepackage{mathabx}

\begin{document}
$\bigtimes_{n=1}^k$
\end{document}


Without package:

\documentclass{article}

% mathabx

\DeclareFontFamily{U}{mathx}{\hyphenchar\font45}
\DeclareFontShape{U}{mathx}{m}{n}{
<5> <6> <7> <8> <9> <10>
<10.95> <12> <14.4> <17.28> <20.74> <24.88>
mathx10
}{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareFontSubstitution{U}{mathx}{m}{n}
\DeclareMathSymbol{\bigtimes}{1}{mathx}{"91}

\begin{document}
$\bigtimes_{n=1}^k$
\end{document}


# LuaTeX/XeTeX with unicode-math

As David Carlisle has written in his answer, the symbol is a Unicode symbol:

U+2A09 n-ary times operator


It can be used directly or via command \bigtimes with package unicode-math and TeX engines, which support OpenType fonts (LuaTeX, XeTeX).

Example with different fonts:

\documentclass[fleqn]{article}

\usepackage{unicode-math}

\begin{document}
\newcommand*{\test}[1]{%
\setmathfont{#1.otf}%
$\bigtimes_{n=1}^k\quad \mbox{\footnotesize(#1)}%$%
}
\test{latinmodern-math}
\test{Asana-Math}
\test{xits-math}
\test{texgyrebonum-math}
\test{texgyrepagella-math}
\test{texgyreschola-math}
\test{texgyretermes-math}
\end{document}


• aha, I've updated my answer to refer to yours for classic TeX:-) – David Carlisle Sep 22 '14 at 11:36
• @DavidCarlisle I am referencing back and have added a full example with differernt fonts. – Heiko Oberdiek Sep 22 '14 at 12:14

Is this what you mean? Here are two variants, using answer from How are big operators defined?

\documentclass{article}
\usepackage{amsmath}
\usepackage{amsfonts}
\DeclareMathOperator*{\foo}{\scalerel*{\times}{\sum}}
\DeclareMathOperator*{\barr}{\scalerel*{\times}{\textstyle\sum}}
\usepackage{scalerel}

\begin{document}
$\foo_{i=3}^{6}(f^2(i))$

This is inline: $$\foo_{i=3}^{6}(f^2(i))$$

$\barr_{i=3}^{6}(f^2(i))$

This is inline: $$\barr_{i=3}^{6}(f^2(i))$$
\end{document}


• It,s not like "\times". It is like "X". I want to write like "\times" with limits. – 6-0 Sep 22 '14 at 11:13
• @hamed Please see revision – Steven B. Segletes Sep 22 '14 at 11:14

Unicode has this symbol as U+2A09 (⨉) so if you are using a unicode engine (xetex or luatex) you can use that symbol directly or use \bigtimes with unicode-math package. See Heiko's answer to access fonts for classic TeX that have this symbol..