Exposed positive maps: a sufficient condition
Dariusz Chruściński, Gniewomir Sarbicki · Journal of Physics A Mathematical and Theoretical · 2012
Exposed positive maps in matrix algebras define a dense subset of extremal maps. We provide a sufficient condition for a positive map to be exposed. This is an analogue of a spanning property which guarantees that a positive map is optimal. We analyze a class of decomposable maps for which this condition is also necessary.