A classification of classical representations for quantum-like systems
  For general non-classical systems, we study the different classical representations that fulfill the specific context dependence imposed by the hidden measurement system formalism introduced in quant-ph/0008061. We show that the collection of non-equivalent representations has a poset structure. We also show that in general, there exists no 'smallest' representation, since this poset is not a semi-lattice. Then we study the possible representations of quantum-like measurement systems. For example, we show that there exists a classical representation of finite dimensional quantum mechanics with ${\Bbb N}$ as a set of states for the measurement context, and we build an explicit example of such a representation. 
Bob Coecke