# How to say the notation $x_{i,j}^{ k}$ [closed]

$x_{i,j}^{ k}$

May I say the following to say the above notation?

x sub i j to k ?

x sub i j sup(prounced like "soup") k ? (Can I say "soup" for "superscript"?

Could you please show me a proper way to say the above notation?

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## closed as primarily opinion-based by Najib Idrissi, Grigory M, Michael Medvinsky, cactus314, quidDec 14 '15 at 13:30

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise.If this question can be reworded to fit the rules in the help center, please edit the question.

You could just... not? If you're talking to someone about tensors with $3$ indices it's probably time to break out the paper or chalkboards. – Qiaochu Yuan Jul 28 '12 at 23:15
@everyone I've created the tag pronunciation. Please let me know if this a bad idea. – user2468 Jul 28 '12 at 23:16
There might be something useful in the references in the previous question, Is there a definitive guide to speaking mathematics? – Rahul Jul 28 '12 at 23:23
@RahulNarain, Thank you for the very useful reference!! – Tony Jul 28 '12 at 23:31
I would avoid saying "sup" and use "super" if needed (sub/super are both Latin prefixes), and I think "sup" might be easily heard as "sub". – Andrew Jul 29 '12 at 2:01

IMHO: If all of the items have the same sub/super script structure (such as tensors with the same index patterns), then I don't see any harm in saying the indeces without saying "sub" or "sup". For example, I'd say "$x$ $i$ $j$ $k$" for $x_{i,j}^k$. In lectures, this works out just fine, especially when accompanied by the symbol $x_{i,j}^k$ on the board.

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Thank you very much. That's a great tip!! – Tony Jul 29 '12 at 8:14
@Andrew, Thank you for your advice!! – Tony Jul 29 '12 at 8:16

As long as you're understood I don't think there's a proper way. I would say "soup" or "super" and I am a native English speaker.

But there may also be a different way to talk about it (e.g., "All the upper indices do X" or "Those dimensions vanish") depending on your final message.

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If the superscript $k$ is an exponent and $i,j$ are indices, I would say "x sub i j to the k", or even "x i j to the k", or least ambiguously "the k'th power of x sub i j". If $x_{i,j}^{k}$ has some other meaning then "x sub i j sup k" is a fine way to refer to how the expression is written but I would prefer the other phrase when raising $x_{i,j}$ to the power of $k$ is what is meant.

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