A class of exposed indecomposable positive maps
  Exposed positive maps in matrix algebras define a dense subset of extremal maps. We provide a class of indecomposable positive maps in the algebra of 2n x 2n complex matrices with n>1. It is shown that these maps are exposed and hence define the strongest tool in entanglement theory to discriminate between separable and entangled states. 
Gniewomir Sarbicki, Dariusz Chru\'sci\'nski
quant-ph math-ph math.MP