Hyperentanglement witness
  A new criterium to detect the entanglement present in a {\it hyperentangled state}, based on the evaluation of an entanglement witness, is presented. We show how some witnesses recently introduced for graph states, measured by only two local settings, can be used in this case. We also define a new witness $W_3$ that improves the resistance to noise by increasing the number of local measurements. 
Giuseppe Vallone, Raino Ceccarelli, Francesco De Martini, Paolo   Mataloni