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I have used i, j, k, and \ell as indexing subscripts.

Now, I would like to write another equation with i and j, but keeping it clear that these are distinct indexes. I would prefer not to have to start going to more esoteric letters (as suggested in response to a related question at math.SE)

Is there a font that will allow me to re-use i and j in two distinct equations?

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Abe
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    Using primes might be a better choice typographically than using typeface distinctions... – kgr Jul 13 '12 at 17:31
  • i,j,k are also esoteric letters depending on the context. There is no standard for indices. – percusse Jul 13 '12 at 17:32
  • α, β, γ, ... are often seen as indices. – Caramdir Jul 13 '12 at 17:39
  • @Caramdir good idea, although in this case beta is the variable being indexed – Abe Jul 13 '12 at 17:49
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    I strongly urge you to use primes or other letters (even if they look esoteric to you). It is very unlikely that you'll find two fonts whose lower case i's are different enough for a reader in a hurry (and there is no other kind) to easily see the difference between -- especially at subscript size. – Mark Meckes Jul 13 '12 at 18:16
  • @MarkMeckes thanks for the advise. I am on the hunt for an esoteric letter; I guess \iota is out, but \gamma, \mathfrak{t}, and t are on the current short-list – Abe Jul 13 '12 at 18:32
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    For what it's worth, personally I frequently use p and q, once i-n are all used up. – Mark Meckes Jul 14 '12 at 12:36

2 Answers2

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The basic options are

\documentclass{article}
\usepackage{mathrsfs,eufrak,bbold}

\begin{document}
    $i,\mathtt{i}, \mathbf{i}, \mathrm{i},\mathsf{i}, \mathfrak{i}, \mathbb{i}, \imath$
\end{document}

enter image description here

See also How to look up a symbol or identify a math symbol or character? Table 213 in symbols-a4.pdf gives a good overview of those different math fonts.

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bodo
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You can af course use \mathbf{i} or \mathsf{i}.

However, I would recommend you to use \tilde{i}, i' or similar to distinguish between different indices.

yo'
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