# [texhax] \ldots v. \cdots

Tue Mar 3 22:37:13 CET 2009

On Tue, 3 Mar 2009, Lars Madsen wrote:

> Karl Ove Hufthammer wrote:
>> P. R. Stanley:
>>
>>> I've come across both \ldots and \cdots in typesetting series in \sum
>>> -- \{1 + 2 + 3 + ldots + n\}. What would the list recommend?
>>
>> I’m surprised nobody has mentioned the AMS recommendations. The document
>> ‘Short Math Guide for LaTeX’ at http://www.ams.org/tex/amslatex.html says
>>
>>         4.6. Dots For preferred placement of ellipsis dots
>>         (raised or on-line) in various contexts there is no
>>         general consensus. It may therefore be considered a
>>         matter of taste. By using the semantically oriented
>>         commands
>>         * \dotsc for “dots with commas”
>>         * \dotsb for “dots with binary operators/relations”
>>         * \dotsm for “multiplication dots”
>>         * \dotsi for “dots with integrals”
>>         * \dotso for “other dots” (none of the above)
>>         instead of \ldots and \cdots, you make it possible for
>>         the fly, in case (for example) you have to submit it to
>>         a publisher who insists on following house tradition in
>>         this respect. The default treatment for the various kinds
>>         follows American Mathematical Society conventions:
>>
>>         We have the series $A_1,A_2,\dotsc$,
>>         the regional sum $A_1+A_2+\dotsb$,
>>         the orthogonal product $A_1A_2\dotsm$,
>>         and the infinite integral
>>         $\int_{A_1}\int_{A_2}\dotsi$.
>>
>
> well aware, but try teaching that to users...

You can use \dots, which converts to one of the above behind the scenes
depending on context (the change of dots depends on the next symbol). For
example,

We have the series $A_1,A_2,\dots,A_n$, the regional sum
$A_1+A_2+\dots+A_n$, the orthogonal product $A_1 A_2 \dots A_n$,
and the infinite integral
$\int_{A_1}\int_{A_2}\dots$.

Much easier than having to worry about which dots to use (but it is wrong
sometimes, like in $A_1 A_2 \dots A_n$ above)