ohm-plugin-prolog is closed source package [1], but open source replacement exists [2], and from quick glance at the sources I can tell you it evaluates rules from /usr/share/policy/rules/current/ directory for audio levels (revised the two files in that directory, too).

prolog-extensions is also a closed source package [1], but open source replacement exists, too [3]. It looks like it provides file /usr/lib/prolog/extensions/fact.so, which source [4] suggests it may be related to the audio stuff, too (a "bridge" ohm-fact <-> prolog-fact), but if you want to be 100% sure, you should inspect that by yourself, I just briefly looked through the code. If you asked me whether you can remove these packages I would rather say "no, I think the audio system strongly needs them".

[1] http://wiki.maemo.org/Fremantle_closed_packages
[2] https://gitorious.org/maemo-multimed...4e0:ohm-plugin
[3] https://meego.gitorious.org/maemo-mu...4e0/extensions
[4] https://gitorious.org/maemo-multimed...ions/pl_fact.c