کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
6415192 | 1334962 | 2014 | 22 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Spectral sets and distinguished varieties in the symmetrized bidisc Spectral sets and distinguished varieties in the symmetrized bidisc](/preview/png/6415192.png)
We show that for every pair of matrices (S,P), having the closed symmetrized bidisc Î as a spectral set, there is a one dimensional complex algebraic variety Î in Î such that for every matrix valued polynomial f(z1,z2),âf(S,P)â⩽max(z1,z2)âÎâf(z1,z2)â. The variety Î is shown to have the determinantal representationÎ={(s,p)âÎ:det(F+pFââsI)=0}, where F is the unique matrix of numerical radius not greater than 1 that satisfiesSâSâP=(IâPâP)12F(IâPâP)12. When (S,P) is a strict Î-contraction, then Î is a distinguished variety in the symmetrized bidisc, i.e. a one dimensional algebraic variety that exits the symmetrized bidisc through its distinguished boundary. We characterize all distinguished varieties of the symmetrized bidisc by a determinantal representation as above.
Journal: Journal of Functional Analysis - Volume 266, Issue 9, 1 May 2014, Pages 5779-5800