Concerning the Cesaro matrix and its immediate offspring

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Crawford Rhaly

Abstract

For the Cesaro matrix C 2 B(l2) and the unilateral shift U, it is known that C and its immediate ospring UCU are both hyponormal and noncompact, and they have the same norm and the same spectrum. Here we investigate similarityand unitary equivalence for C and U*CU, as well as further generations of ospring.Necessary conditions are found for a lower triangular factorable matrix to be unitarily equivalent to its immediate ospring. A specialized result is obtained for factorable matrices having a constant main diagonal. Along the way, a more generalresult is also obtained: necessary conditions are found for two lower triangular factorable matrices to be unitarily equivalent.

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How to Cite
Rhaly, C. (2014). Concerning the Cesaro matrix and its immediate offspring. Acta Mathematica Universitatis Comenianae, 84(1), 27-38. Retrieved from http://www.iam.fmph.uniba.sk/amuc/ojs/index.php/amuc/article/view/28/122
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