论文标题

通过Berger-coburn-lebow定理杰出品种

Distinguished Varieties Through the Berger--Coburn--Lebow Theorem

论文作者

Bhattacharyya, Tirthankar, Kumar, Poornendu, Sau, Haripada

论文摘要

$ \ Mathbb {C}^2 $中的杰出代数品种近年来一直是许多研究的重点。该注释给出了不同的观点。 (1)我们发现了代数品种$ \ Mathcal W $的新特征,该$ \ Mathcal W $与Bidisc相关。就一对通勤线性基质铅笔的关节频谱而言。 (2)由于Agler和McCarthy的开创性作品,有$ \ Mathbb {D}^2 \ Cap \ Mathcal {W} $已知的特征。我们表明,Agler-麦卡锡的表征可以从新的表征获得,反之亦然。 (3)在途中,我们为单位光盘上的运算符价值合同分析功能开发了一个新的实现公式。 (4)在操作员有价值的合同塑形函数和{\ em canonical模型三元}之间有一对一的对应关系。这与上面提到的新实现公式有关。 (5)PAL和Shalit对代数品种的表征,该代数相对于对称的Bidisc而言,其数值半径不超过$ 1 $。我们通过使矩阵的类别严格较小来完善它们的结果。 (6)在两个以上变量的方向上的概括中,我们表征了所有相对于polydisc而区分的一维代数品种。 我们作品的根源是伯格(Berger-boburn) - lebow定理,表征了元组的元组。

A distinguished algebraic variety in $\mathbb{C}^2$ has been the focus of much research in recent years because of good reasons. This note gives a different perspective. (1) We find a new characterization of an algebraic variety $\mathcal W$ which is distinguished with respect to the bidisc. It is in terms of the joint spectrum of a pair of commuting linear matrix pencils. (2) There is a characterization known of $\mathbb{D}^2\cap\mathcal{W}$ due to a seminal work of Agler and McCarthy. We show that Agler--McCarthy characterization can be obtained from the new one and vice versa. (3) En route, we develop a new realization formula for operator-valued contractive analytic functions on the unit disc. (4) There is a one-to-one correspondence between operator valued contractive holomorphic functions and {\em canonical model triples}. This pertains to the new realization formula mentioned above. (5) Pal and Shalit gave a characterization of an algebraic variety, which is distinguished with respect to the symmetrized bidisc, in terms of a matrix of numerical radius no larger than $1$. We refine their result by making the class of matrices strictly smaller. (6) In a generalization in the direction of more than two variables, we characterize all one-dimensional algebraic varieties which are distinguished with respect to the polydisc. At the root of our work is the Berger--Coburn--Lebow theorem characterizing a commuting tuple of isometries.

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