No variadic cartesian product symbol

[rdong8]

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I would like to denote the cartesian product of an arbitrary number of sets, similarly to how $\bigcup_i A_i$ gives the union of $n$ sets.

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Possibly extract the code from the mathabx package that provides the $\bigtimes$ symbol and include it into KaTeX? That is the recommended solution here.

Link to or name of a (La)TeX package that provides the same feature:
KaTeX's general goal is to render as LaTeX does.

mathabx: https://ctan.org/pkg/mathabx?lang=en

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Using the regular $\times$ symbol, but it doesn't look right: $D_y = \{ (x_i)_{i=1}^n \in \times_{i=1}^n \operatorname{range}(X_i) : g(x_i)_{i=1}^n = y \}$.

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I am using the KaTeX included in Notion if that is relevant.

[edemaine]

I believe \prod is somewhat standard for this setting, and supported by KaTeX.

\bigtimes is a reasonable ask, though. mathabx seems to implement it with a font, which is complicated to add to KaTeX. But mathtools seems to do it with "simple" macros:

https://github.com/latex3/mathtools/blob/58d14613fc469718fe85849dfcfcee2a605c2b2b/mathtools.dtx#L5877-L5916

Basically, some resizing (different in different styles) and some vertical centering. KaTeX doesn't support \vcenter though, so this is a little tricky. Here's an approximation in your example:

D_y = \{ (x_i)_{i=1}^n \in {\raisebox{-.2em}{\LARGE$\times$}}_{i=1}^n \operatorname{range}(X_i) : g(x_i)_{i=1}^n = y \}

Probably we could write a general macro (with \mathchoice) that gets the size and vertical spacing right. Feel free to submit a PR!