How to force arXiv.org to run pdflatex

Here is a useful trick worth remembering. If you want to force arXiv.org to run pdflatex and not old latex on your tex file you need to stick \pdfoutput=1 in the first 5 lines of your tex file (see here). Latex, being nothing but a front for pdflatex anyway, will then effectively run pdflatex and directly create a pdf.

Note that this means that can't create a dvi or ps file by running latex anymore with that tex file even if you are using the ifpdf package and running latex from the command line.