A simple derivation of the strong subadditivity inequalities
  In this short note, we give a simple derivation of the strong subadditivity inequalities: S(13) + S(23) \ge S(1) + S(2) and S(12) + S(23) \ge S(2) + S(123). The simplicity is due to the way we represent the quantum systems. We make a few remarks about such a representation. 
S. Kalyana Rama
quant-ph cond-mat.stat-mech gr-qc hep-th