It would be convenient for everyone involved if a set of standard style files was used on PM. This would make notation consistent throughout the site, and would prevent lots of potential LaTeX errors when we go to combine the various entries in the FEM.
I think it would be ideal if people always added new definitions to these central files, though a more liberal approach would allow a mixture of standard style file inclusions and ad hoc definitions in the file itself. We can talk more about the relative merits of these two approaches.