Systems of subspaces of a unitary space
  For a given poset, we consider its representations by systems of subspaces of a unitary space ordered by inclusion. We classify such systems for all posets for which an explicit classification is possible. 
Vitalij M. Bondarenko, Vyacheslav Futorny, Tatiana Klimchuk, Vladimir   V. Sergeichuk, Kostyantyn Yusenko
math.RT