DC FieldValueLanguage
dc.contributor.authorGau, Hwa-Longen_US
dc.contributor.authorWu, Pei Yuanen_US
dc.date.accessioned2014-12-08T15:34:38Z-
dc.date.available2014-12-08T15:34:38Z-
dc.date.issued2014-01-01en_US
dc.identifier.issn0024-3795en_US
dc.identifier.urihttp://dx.doi.org/10.1016/j.laa.2013.11.013en_US
dc.identifier.urihttp://hdl.handle.net/11536/23640-
dc.description.abstractWe derive a matrix model, under unitary similarity, of an n-by-n matrix A such that A, A(2),, A(k) (k >= 1) are all partial isometries, which generalizes the known fact that if A is a partial isometry, then it is unitarily similar to a matrix of the form [(0 B)(0 C)] with B*B +C*C =1. Using this model, we show that if A has ascent k and A, A(2),..., Ak(-1) are partial isometries, then the numerical range W (A) of A is a circular disc centered at the origin if and only if A is unitarily similar to a direct sum of Jordan blocks whose largest size is k. As an application, this yields that, for any S-n-matrix A, W (A) (resp., W (A circle times A)) is a circular disc centered at the origin if and only if A is unitarily similar to the Jordan block J(n). Finally, examples are given to show that, for a general matrix A, the conditions that W (A) and W (A circle times A) are circular discs at 0 are independent of each other. (C) 2013 Elsevier Inc. All rights reserved.en_US
dc.language.isoen_USen_US
dc.subjectPartial isometryen_US
dc.subjectPower partial isometryen_US
dc.subjectNumerical rangeen_US
dc.subjectS-n-matrixen_US
dc.subjectJordan blocken_US
dc.titleStructures and numerical ranges of power partial isometriesen_US
dc.typeArticleen_US
dc.identifier.doi10.1016/j.laa.2013.11.013en_US
dc.identifier.journalLINEAR ALGEBRA AND ITS APPLICATIONSen_US
dc.citation.volume440en_US
dc.citation.issueen_US
dc.citation.spage325en_US
dc.citation.epage341en_US
dc.contributor.department應用數學系zh_TW
dc.contributor.departmentDepartment of Applied Mathematicsen_US
dc.identifier.wosnumberWOS:000329557700026-
dc.citation.woscount1-
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