[AUCTeX] force a given style (multi-file)

[guille]

Hi,

I have a big beamer document split into several files, which get included in the
main one with \input. The main one has the \documentclass{beamer} declaration,
so when it is loaded the beamer.el style is used. But the other files, which do
not have the declaration do not use the style when loaded.

Is there a way to require the beamer.el style in those files? for example using
some local variable?

thanks,

guille