# I Subscript help

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1. Dec 30, 2016

I am almost ashamed to put this question, as it verges on the silly, but it is a real question, and Physics Forums has come to my rescue so often....
I am translating a physics article from Russian, and at one place the author puts quantities (such as σ for standard deviation, etc.) with a double subscript: one indicating the particle involved, and the second the axis upon which the quantity is projected. I am not one to ask the author to change his style (let alone the content), but I do have to change the Russian letter he uses for "particle" to an English subscript. He uses the first letter of the Russian word for "particle", so that with a projection to the x-axis, this looks like σчx. If I used "p", this would look too much like momentum. I can't think of another natural single letter. Any suggestions?
I could then use a syllable instead of a letter: if I use, say, "par", then I have to come up with a natural way to combine them (without second-level subscripts such as σparx or σxpar): parx is obviously no good, but I am not sure about something like par(x), par-x, par.x, or par/x. So, any suggestions?
Thanks.

2. Dec 30, 2016

### Staff: Mentor

$\sigma_{par,x}$?
If the particle has some index or name, that could be used.

3. Dec 30, 2016

Thanks for the suggestion, mfb. That sounds pretty good.
(But I am willing to hear other suggestions, for anyone else who reads this.)
Unfortunately, the generalized particle has no particular name; the author is trying to prove statements about particles in chaotic motion around a central point (no, not Brownian motion), and although he sometimes uses an electron as an example, the statements are supposed to be general. So no particular name. Alas.

4. Dec 31, 2016

### Staff: Mentor

Does the article refer to any articles in English? If so, those might give examples of the customary notation for that field.

5. Dec 31, 2016