8

\cdots and \dotsm, which I presume to stand for center dots and dots for multiplication, are both three dots in the middle of the line. I don't see the difference between them, and which is better to use in defining a variable like this?

Code: S = 1!2! \dotsm 100!

Output: S = 1!2!...100!

Similar question (not a duplicate): What is the difference between ‎\ldots‎ and ‎\cdots‎?

ᴇɴᴅᴇʀᴍᴀɴ
  • 191
  • 8
  • 1
    As is customary on this site, please show compilable code (Minimal Working Example). The two commands you mentioned don't exist in default LaTeX so it's impossible to reproduce your result and suggest anything. Thank you. – Miyase Jul 05 '22 at 22:42
  • 1
    @Enderman note any version in a javascript emulation such as mathjax is off topic here, I answered the question assuming you were asking about latex. – David Carlisle Jul 05 '22 at 22:47
  • @DavidCarlisle I'm using AoPS, so try doing it on the AoPS TeXer: https://artofproblemsolving.com/texer. Also, I think AoPS uses amsmath. – ᴇɴᴅᴇʀᴍᴀɴ Jul 05 '22 at 22:50
  • 1
    @Enderman ah so actually they are using tex (for the pdf option): This is pdfTeX, Version 3.141592653-2.6-1.40.22 (TeX Live 2021) although they also show a mathjax option – David Carlisle Jul 05 '22 at 22:55
  • @DavidCarlisle didn't know what AoPS used for LaTeX rendering so wasn't sure which tag to put there. What tags should I tag my post then? – ᴇɴᴅᴇʀᴍᴀɴ Jul 05 '22 at 22:58
  • 1
    amsmath as it is now is fine – David Carlisle Jul 05 '22 at 22:58
  • @DavidCarlisle, After some research, I looked at https://artofproblemsolving.com/wiki/index.php/LaTeX:Packages and figured out that AoPS indeed does use amsmath. So I was correct. – ᴇɴᴅᴇʀᴍᴀɴ Jul 05 '22 at 23:33
  • 2
    Unrelated to the question, but your example might look better with a thinspace (\,) between 1! and 2!. – mickep Jul 06 '22 at 05:21
  • @mickep I'm fairly new (not that new) at LaTeX stuff so could you explain what that does? Does it just make it look better or something? – ᴇɴᴅᴇʀᴍᴀɴ Jul 06 '22 at 16:36
  • 1
    The \, inserts a thinmuskip which is 3mu by default. You can have a look at this answer to see the difference and judge for yourself if it is worth it. – mickep Jul 06 '22 at 16:48
  • @mickep Took a look, I don't think it is worth it so I will just leave it at that. – ᴇɴᴅᴇʀᴍᴀɴ Jul 06 '22 at 17:18
  • 1
    \dotsm stands for "dots for multiplication", not "dots middle". It's part of the "semantic dots" group that includes \dotsb "dots for binary operators", \dotsc "dots for commas", and \dotsi "dots for integrals". (I don't know when one should use \dotsb versus \dotsm when the binary operator is multiplication; I think perhaps the former is appropriate with an explicit operator symbol, and the latter when the operator is left implicit.) – LSpice Jul 06 '22 at 19:57
  • 1
    @LSpice didn’t know that, fixed my post! – ᴇɴᴅᴇʀᴍᴀɴ Jul 06 '22 at 20:52

1 Answers1

19

\cdots is defined in the LaTeX format. \dotsm is an alias in amsmath, defined as

\let\dotsm\cdots

So, \cdots and \dotsm are identical.

Svend Tveskæg
  • 31,033
David Carlisle
  • 757,742