6

Consider the center dots to show repeated multiplication:

\[
x \cdot x \cdot x \cdots x.
\]

I want to use five dots instead of the three from the \cdots command, and I also want to have them subtly arced like on the path of part of a downward-opening parabola or something.

Does such a command already exist? If not, is it possible to create such a command or achieve it on a one-off/as-needed basis?

pdfLaTeX user.

2
  • The purpose of this is visual. I think it might add a touch of visual stimulation to my written explanations or illustrative examples to students. Commented Nov 30, 2021 at 23:32
  • Why not $x \cdot x \cdot \ldots \cdot x$? Commented Dec 8, 2021 at 11:23

2 Answers 2

7

If the horizontal spacing needs changing, that can be done with kerns. If it is needed in smaller (script) mathstyles, let me know in a comment and I will revise my answer to provide them.

\documentclass[10pt]{article}
\usepackage{amsmath}
\newcommand\repdots{\mathbin{{\cdot}\raisebox{.75pt}{$\cdot$}%
  \raisebox{1pt}{$\cdot$}\raisebox{.75pt}{$\cdot$}{\cdot}}}
\begin{document}
$x \cdot x \cdot x \cdots x.$

$x \cdot x \cdot x  \repdots x.$
\end{document}

enter image description here

SUPPLEMENT to add extra \cdot kern (also supports smaller mathstyles)

The value of \dotkern is used to space out the \cdots. The value 1\LMpt (Local Math pt) is 1 pt in text and display styles, but proportionately smaller in the smaller math styles.

\documentclass[10pt]{article}
\usepackage{amsmath,scalerel}
\newcommand\dotkern{\kern1\LMpt}
\newcommand\repdots{\mathbin{\ThisStyle{{\cdot}\dotkern%
  \raisebox{.75\LMpt}{$\SavedStyle\cdot$}\dotkern
  \raisebox{1\LMpt}{$\SavedStyle\cdot$}\dotkern%
  \raisebox{.75\LMpt}{$\SavedStyle\cdot$}\dotkern{\cdot}}}}
\begin{document}
$x \cdot x \cdot x \cdots x.$

$x \cdot x \cdot x  \repdots x.$

$\scriptstyle x \cdot x \cdot x  \repdots x.$

$\scriptscriptstyle x \cdot x \cdot x  \repdots x.$
\end{document}

enter image description here

5
  • 2
    To make it truly parabolic change .7pt to .75 pt: \newcommand\repdots{\mathbin{{\cdot}\raisebox{.75pt}{$\cdot$}\raisebox{1pt}{$\cdot$}\raisebox{.75pt}{$\cdot$}{\cdot}}}
    – Dan
    Commented Nov 30, 2021 at 20:40
  • @Dan LOL :-)...I like the parabolic dots :-))))
    – Sebastiano
    Commented Nov 30, 2021 at 20:42
  • 3
    Thanks, @Dan. If I had given it more thought, I should have known that. Retired for 2 months and all my elementary skills evaporate!! Commented Nov 30, 2021 at 20:46
  • Perfect! How to adjust the horizontal spacing so that it is the same as in \cdots or ever so slightly closer? Commented Nov 30, 2021 at 20:58
  • 2
    @UngarLinski Please see my SUPPLEMENT Commented Nov 30, 2021 at 21:06
4

Steven's answer is excellent, but just for fun we can make a macro for arbitrary dots and curvature.

Use as follows: \repdots{# dots}{max vertical displacement in pt}.

\documentclass{article}
\usepackage{pgffor}
\usepackage[nomessages]{fp}
\newcommand\repdots[2]{\mathbin{\foreach \n in {1,...,#1}{\FPeval\temp{(-((\n-1)/(#1-1))*((\n-1)/(#1-1)-1)*4*(#2))}\raisebox{\temp pt}{$\cdot$}}}}
\begin{document}
$x \repdots{5}{1} x \repdots{4}{-3} x \repdots{30}{6} x \repdots{7}{-2} x$\\
\end{document}

enter image description here

3
  • 2
    Excellent answer also this :-)...more parabolic.....
    – Sebastiano
    Commented Nov 30, 2021 at 21:46
  • Now can we spell out my name in cursive with the dots? :) Commented Nov 30, 2021 at 23:27
  • 1
    @UngarLinski Easier to do something like tex.stackexchange.com/questions/96766/… to make letters.
    – Dan
    Commented Dec 1, 2021 at 0:19

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .