40

Assume I wish to refer to the i-th object, or the n-th function out of some set, where i and n are letters and not numbers (as in "Multiply the $j$th row with the $i$th column and store the result in the $k$th memory cell, where $k=i+j$")

How do you suggest to write it?

$n$th is just confusing, $n$-th seems weird, and $n^{\text{th}}$, which is my current choice, is (pardon me) simply ugly.

Any suggestions?

9
  • 8
    My preferred form is "$n$-th". Feb 13, 2011 at 8:23
  • 7
    I think we've had this before...
    – Seamus
    Apr 4, 2011 at 16:50
  • 3
    Note that the meaning of the question is where "n" is a letter , rather than a number (e.g. the "i-th" element, the k-th index and the n-th dimension). The other question is specific to numbers (e.g., 1st, 2nd, etc.).
    – Ran G.
    Jun 4, 2012 at 3:10
  • 5
    @RanG. I agree. My preferred forms would be "multiply row~$j$ with column~$i$" or "multiply the $j$-th row with the $k$-th column". The "th" at exponent is too ambiguous in a math context (and simply ugly in general).
    – egreg
    Jun 5, 2012 at 10:54
  • 1
    Does this answer your question? What's the quickest way to write "2nd" "3rd" etc in LaTeX?
    – user202729
    Nov 4, 2021 at 4:57

5 Answers 5

18

In my experience $n$th is most widely used (like here). Personally I don't think it's ugly compared to the other two options and I think it's quite readable.

5
  • 5
    especially with "i", it looks like a typo of "with" (:
    – Ran G.
    Feb 13, 2011 at 7:28
  • In spite of this being the most widely used option, I often find myself using $n$-th. I'm not sure why exactly, possibly it is because I use $n$-Bonacci, $\beta$-expansion etc. quite a lot.
    – yo'
    Jan 10, 2013 at 10:20
  • 2
    \(n\)th may be more correct if you use LaTeX.
    – N.N.
    Jan 10, 2013 at 11:11
  • @RanG. For i th, would you prefer $i$-th or $i^{th}$ ? Jan 18, 2021 at 6:32
  • @CyriacAntony in recent years I've used $i$-th. Not happy about it, but it is (currently) the best option I see.
    – Ran G.
    Jan 18, 2021 at 12:47
14

AMS Style Guide has a strong opinion on this one.

See section 12.7.5.3.

3
  • 2
    Is it just a taste or is there a reason behind it? I think x-th is more readable.
    – zyy
    Nov 4, 2021 at 12:00
  • 1
    It's meant to be dictatorial. You either follow without questioning or not follow for good reasons.
    – Symbol 1
    Nov 4, 2021 at 16:22
  • If this happens in the statement of a theorem, it is italicized, and $i$th is really looks like ith, with no visual separator between i and th. Which does not look good at all.
    – mathreader
    Sep 28, 2022 at 9:04
11

$n$th is compatible with the command \nth{} which is called-upon by the package nth...

\documentclass{book}
\usepackage{nth}
\begin{document}
\nth{3} is not the same as $\nth{3}$
\end{document}

b.t.w. as far as I know this command only work with numbers...

2
  • 6
    Yeah, I can't make \nth{$i$} work, sadly.
    – Translunar
    Jul 10, 2014 at 19:57
  • 4
    How could they not make \nth work with \nth{$n$)?! Aug 27, 2019 at 21:37
0

I'd suggest to write it as $n$ᵗʰ.

Some more details at https://tex.stackexchange.com/a/621236/112999.

-1

$n^{\text{th}}$ is the best if you want to write nth in TEX.

3
  • 9
    Welcome to TeX.SX! You can have a look at our starter guide to familiarize yourself further with our format. I don't want to disturb you, but (1) this was already proposed in the question itself, so as long as you don't accompany it with any relevant sources, it doesn't bring anything new to the topic, and (2) this is the second most ugly solution, after $n^{\text{\tiny th}}$, so very far from being the best.
    – yo'
    Oct 2, 2014 at 20:12
  • $n^{\textnormal{th}}$ does not require any package!
    – Say OL
    Apr 18, 2018 at 4:06
  • 1
    Why is it the best? Why is it better than the other answers?
    – jvriesem
    Jul 29, 2020 at 16:31

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