In the paper there are three formulations:

i) Basic formulation which tries to find a disjunction of terms to cover each 
to cluster
ii) As above but with composition constraints (together/apart)
iii) A cover or forget variation which can ignore some instances to find compact explanations.

These three formlulations are demonstrated in 
main_basic.m  main_basic_apart_together.m  main_cover_or_forget.m respectively.