On a positive linear map preserving absolute values Original Research Article

Suppose image is an n × n (n greater-or-equal, slanted 2) matrix algebra over a C*-algebra image, and image is a C*-algebra. If image is a positive, disjoint linear map, then φ preserves absolute values. In particular, for a linear map image of C*-algebras, φ preserves absolute values if and only if it is positive and “ultraweakly disjoint.”