Schwarz inequalities and the decomposition of positive maps on C*-algebras
Schwarz inequalities and the decomposition of positive maps on C*-algebras
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Schwarz 不等式和 C* 代数正映射的分解
DOI：
10.1017/s0305004100061144
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发表时间：
1983
影响因子：
0.8
通讯作者：
Guyan Robebtson
中科院分区：
文献类型：
--
作者：
Guyan Robebtson
近年来，关于C ~*-代数中某些保持自然偏序的线性映射的研究取得了相当大的进展。最易处理的这种映射，即完全正映射，已被证明在C*-代数的结构理论中具有重要意义（4）。然而，一般的正（保序）线性映射（目前）是非常棘手的。例如，没有代数公式，使一个构造一般的正映射，即使在代数的3 - 3复杂的矩阵。因此，研究比阳性更强但比完全阳性更弱的条件是很有趣的。
In recent years there has been considerable progress in the study of certain linear maps of C*-algebras which preserve the natural partial ordering. The most tractable such maps, the completely positive ones, have proved to be of great importance in the structure theory of C*-algebras(4). However general positive (order-preserving) linear maps are (at present) very intractable. For example, there is no algebraic formula which enables one to construct a general positive map, even on the algebra of 3 3 complex matrices. It is therefore of interest to study conditions stronger than positivity, but weaker than complete positivity.