It’s been a while since a TeX-related post here, but I still use TeX and friends once in a while, and this time I’d like to share something apparently not everyone knows about.

LaTeX has a `\dots`

macro, setting the ellipsis (three consecutive dots) which is just an alias for `\ldots`

. It also has `\cdots`

, which is similar, but the dots are centered vertically (at the level of things like a plus sign). And you should generally use `\cdots`

between operators like `+`

or `\times`

(so that the dots are vertically aligned with them) and `\ldots`

between punctuation like commas (so that the dots are vertically aligned with them).

Also, when you use the `amsmath`

package, you can just use `\dots`

all (or most) of the time. It uses a clever trick of looking (more or less) at the *next* character after the ellipsis to determine if they should be `\ldots`

or `\cdots`

. One exception is when you have stuff like `$1+2+\cdots$`

, where the “next character” is not a math operator, so LaTeX needs a small hint that centered dots are needed here.

And that’s it. There is more to know, as usual, but the advice above should cover at least 95% cases.