本文给出C*-代数之间完全正映射的刻画,证明:如果A,B是有单位元的C·-代数,则映射西:A→B为完全正映射当且仅当存在保单位·-同态πA:A→B(K)、等距·-同态丌B:B→B(H)及有界线性算子V:H→K,使得πB(Ф(1))=v。V且 ∈A,都有丌B(西(Ф))=V·π(α)V.作为推论,得到著名的Stinespring膨胀定理.
In this paper, we give the characterization of completely positive mappings on C* -algebra. It is proved that if A and B are C -algebras with identity, Ф A → B is a com- pletely positive mapping if and only if there are a unit-preserving * -homomorphism πA : A → B(K) ,an isometric "-homomorphism rca " B → B(H) and a bounded linear operator V : H→ Ksuch that πB(Ф(1)) = V = V and πB( Cp( a ) ) = V* π A ( a ) V , a ∈ A. Meanwhile,we get the famous Stinespring's dilation theorem as a corollary.