Abstract: For two positve maps, we construct a new linear map, by means of some additional ingredients such as operators and functionals. We call it a merging of maps. The properties of this construction are discussed. In particular, conditions for positivity, as well as for 2-positivity, completely positivity, optimality and indecomposability are provided. In particular, we show that for a pair composed of completely positive and completely positive maps, there is an indecomposable merging of them. One of our main results asserts, that for a canonical merging of a pair composed of completely positive and completely copositive extremal maps, their canonical merging is an exposed positive map. This result provides a wide class of new examples of exposed positive maps. As an application, new examples of entangled PPT states are described.
