Incase anyone else is looking for some more background to understand this:
http://pckipo.blogspot.com.au/2009/09/c-sets-and-l-sets-draft.html
PC: what your previous blog post, and this post, is missing is showing/explaining some examples of these different kinds of sets in Lojban. This would be quite helpful if you want to promote usage.
Andrew / DerSaidin