# A MathJax/LaTeX question

In This question, the following appears:

$$[0,2] \times \left[0,4-\sqrt{3}\right] \times \left[0,4-\sqrt{3}\right] \times \mathop{\Large\times}_{i=1}^{k-3}[0,2]$$

Thinking that that last $$\times$$ should be somewhat comparable in size to $$\sum$$ or $$\prod$$ or $$\bigoplus$$ or $$\bigcup,$$ I tried changing it to this: $$[0,2] \times \left[0,4-\sqrt{3}\right] \times \left[0,4-\sqrt{3}\right] \times \mathop{\Huge\times}_{i=1}^{k-3}[0,2]$$ The subscript $$i=1$$ definitely seems too high. Contrast these: $$\begin{array}{c} \displaystyle \sum_{i=1}^{k-3} [0,2] \qquad\qquad \mathop{\Huge\times}_{i=1}^{k-3} [0,2] \qquad \qquad \sum_{i=1}^{k-3} [0,2] \\ \hline \end{array}$$ Can this be corrected?

• A related question on TeX - LaTeX: How do you produce sign for set multiplication (from old math book) in LaTeX?. But I don't think \varprod is available in MathJax. (At least in the version currently available on MO and SE.) Neither is \operatornamewithlimits. Commented Jan 31 at 5:07
• In this instance, I think the notation is overkill. The expression $[0,2]^{k-3}$ describes the same product. But the point remains for other cases where it might actually be needed, say if the intervals were of the form $[0,2i]$.
– David Roberts Mod
Commented Jan 31 at 10:41
• Does \raisebox work here? … After experimentation, now edited out, no. Well, if it did, then \raisebox{-experimentally determined amount} might be the easiest solution. But it doesn't. \bigtimes also doesn't work. Commented Jan 31 at 22:58
• By the way, I know some on the MathJax team read MMO, at least for bug reports, so maybe they'll make their feelings known on this issue (how to do it or why it isn't feasible—or maybe, as I often find with my questions, that it could be done if MO would upgrade its MathJax!). Commented Jan 31 at 23:03
• @LSpice This is not a bug report or an issue with MathJax. In real LaTeX, \Huge cannot be used inside a math formula in the first place (so this is a convenience feature of MathJax), but if you replace it with the correct \hbox{\Huge$\times$}, it will behave exactly as seen here: even if wrapped in \mathop, it will be set too high, unless you use \vcenter to correct it. Commented Feb 1 at 9:09
• @EmilJeřábek, re, I meant the absence of \varprod pointed out by @‍MartinSleziak (which is also not a bug report, but may be something that MathJax developers are willing to act on—by "at least for bug reports" I didn't mean "this is a bug report", but rather that, while they weren't necessarily here for this, they might act on it anyway). Commented Feb 1 at 12:13
• Oh, I see. Well, MathJax lacks the txfonts additions as a whole. Commented Feb 1 at 12:32
• @EmilJeřábek, re, sure; I assume that which packages are included is based at least partially on frequency of use, and I assumed that what people on MO would use is a helpful guide to that. But I don't pretend to have any insight into the MathJax development process, so maybe I'm wrong. More to the point, thank you for your guidance in your comment and answer; I learned something new! Commented Feb 1 at 14:22

You need to vertically center the symbol on the math axis: \mathop{\vcenter{\Huge\times}}
$$[0,2] \times \left[0,4-\sqrt{3}\right] \times \left[0,4-\sqrt{3}\right] \times \mathop{\vcenter{\Huge\times}}_{i=1}^{k-3}[0,2]$$ $$\begin{array}{c} \displaystyle \sum_{i=1}^{k-3} [0,2] \qquad\qquad \mathop{\vcenter{\Huge\times}}_{i=1}^{k-3} [0,2] \qquad \qquad \sum_{i=1}^{k-3} [0,2] \\ \hline \end{array}$$
BTW, this only works in MathJax. In real LaTeX, you cannot use \Huge in a math formula: you’d have to write \mathop{\vcenter{\hbox{\Huge$\times$}}}.
(If you were writing an actual macro to support it, you should probably also use \mathchoice to supply different sizes for the four TeX math styles so that it could be used outside of displaystyle, maybe use relative size commands \larger instead of \Huge to adapt to the environments, and you should put \m@th inside the embedded $...$ to reset \mathsurround to 0pt in case someone changed it.)