Packages

> If I define my own abbreviations as follows (no ending space),
>
> \newcommand{\knn}{$k$NN}
>
> I found that the space after the \knn will be eaten

Either call the command like \knn{} to avoid the eating of the space or use the `xspace' package and the command with the same:

\newcommand{knn}{$k$NN\xspace}

\xspace will determine if a space is needed, and if so insert one.

Magnus