# Is there an equivalent to “big pi” for tensor products?

I'd like to be able to rewrite expressions like

$$[f(i,j,k,\ldots)]^{\otimes n}$$


in a form analogous to

$$\prod_{j\in J}f(i,j,k,\ldots)$$


so that I can distinguishing the index being varied and specify its domain.

Is there a notation for tensor products that corresponds to $\prod$?

• How about $\bigotimes$, that is \bigotimes? To use it in a sentence, I guess: $$\bigotimes_{j\in J} f_j$$ – Frank McGovern Mar 22 '13 at 23:55
• @FrankMcGovern: That looks like an answer! But (I know this is more $\LaTeX$ than math), how do I get under it to write the index? – orome Mar 23 '13 at 0:00
• This was migrated from math.se; do you think it was the right thing to do? – egreg Mar 23 '13 at 0:39
• @egreg: I'd have left it in Math.SE (the question is about notation) and asked the $\LaTeX$ question separately here. – orome Mar 23 '13 at 0:48

## 1 Answer

I'll just give the answer here. The \bigotimes notation works great.

\bigotimes_{j\in J}\,f_j

• +1. This notation is standard in the quantum information community. – Niel de Beaudrap Mar 23 '13 at 0:37