A Combinatory-Algebraic Perspective on Multipartiteness, Entanglement   and Quantum Localization
  We claim that both multipartiteness and localization of subsystems of compound quantum systems are of an essentially relative nature crucially depending on the set of operationalistically available states. In a more general setting, to capture the relativity and variability of our structures with respect to the observation means, sheaves of algebras may need be introduced. We provide the general formalism based on algebras which exhibits the relativity of multipartiteness and localization. 
Ioannis Raptis, Roman Zapatrin