]> As for part_of, with the additional constraint that subject and object may be identical http://sswapmeet.sswap.info/obo/owl/PMID#PMID_15892874 PMID:15892874 OBSOLETE. The definition is "As for part_of, with the additional constraint that subject and object may be identical". However, part_of is already reflexive, therefore improper_part_of is identical to part_of. If read differently, as "improper_part_of is part_of but not proper_part_of",improper_part_of becomes identity. So, improper_part_of is either identical to part_of or to identity, and not an intuitive synonym for either of them. [Robert Hoehndorf] relationship improper_part_of