I have noticed that if I use either
pdflatex to compily my
presentation.tex file, I get either serif or non-serif font, respectively. Why is that and how can I control that?
pslatex is a simple shell script that is equivalent to using
latex with the
pslatex package makes the document default to
Times/Helvetica/Courier fonts, which will account for the font change.
pslatex is designed for an era in which the only available fonts were likely to be the original PostScript fonts built into a laserwriter printer, really there is no reason to use either the package or the wrapper shell script these days.
If you just use
latex rather than
pslatex you will get the fonts specified in the document, as for