Academic Journal
The equality case in ‖f(A)‖ ≤ f(‖A‖) for analytic matrix functions under strongly stable norms.
| Τίτλος: | The equality case in ‖f(A)‖ ≤ f(‖A‖) for analytic matrix functions under strongly stable norms. |
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| Συγγραφείς: | Zhang, Teng1 (AUTHOR) teng.zhang@stu.xjtu.edu.cn |
| Πηγή: | Linear Algebra & its Applications. Dec2026, Vol. 750, p154-162. 9p. |
| Θεματικοί όροι: | *Matrix functions, *Matrix norms, *Matrix inequalities, *Operator functions, *Mathematical equivalence, *Spectral theory |
| Περίληψη: | Let ‖ ⋅ ‖ be a strongly stable norm on M n (C) , and let f (z) = ∑ k = 0 ∞ c k z k be analytic in the disc | z | < R , where R ∈ (0 , ∞ ]. Assume that c k ≥ 0 for all k ≥ 0 , that c 0 (‖ I ‖ − 1) = 0 , and that there exists N ≥ 0 such that c N , c N + 1 , ... , c N + n > 0. We prove that for every matrix A ∈ M n (C) satisfying ‖ A ‖ < R , ‖ f (A) ‖ = f (‖ A ‖) ⟺ ‖ A ‖ ∈ σ (A) , where σ (A) is the spectrum of A. Consequently, this resolves a conjecture of Bünger and Rump in [2]. [ABSTRACT FROM AUTHOR] |
| Βάση Δεδομένων: | Academic Search Index |
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| Items | – Name: Title Label: Title Group: Ti Data: The equality case in ‖f(A)‖ ≤ f(‖A‖) for analytic matrix functions under strongly stable norms. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Zhang%2C+Teng%22">Zhang, Teng</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> teng.zhang@stu.xjtu.edu.cn</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Linear+Algebra+%26+its+Applications%22">Linear Algebra & its Applications</searchLink>. Dec2026, Vol. 750, p154-162. 9p. – Name: Subject Label: Subject Terms Group: Su Data: *<searchLink fieldCode="DE" term="%22Matrix+functions%22">Matrix functions</searchLink><br />*<searchLink fieldCode="DE" term="%22Matrix+norms%22">Matrix norms</searchLink><br />*<searchLink fieldCode="DE" term="%22Matrix+inequalities%22">Matrix inequalities</searchLink><br />*<searchLink fieldCode="DE" term="%22Operator+functions%22">Operator functions</searchLink><br />*<searchLink fieldCode="DE" term="%22Mathematical+equivalence%22">Mathematical equivalence</searchLink><br />*<searchLink fieldCode="DE" term="%22Spectral+theory%22">Spectral theory</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Let ‖ ⋅ ‖ be a strongly stable norm on M n (C) , and let f (z) = ∑ k = 0 ∞ c k z k be analytic in the disc | z | < R , where R ∈ (0 , ∞ ]. Assume that c k ≥ 0 for all k ≥ 0 , that c 0 (‖ I ‖ − 1) = 0 , and that there exists N ≥ 0 such that c N , c N + 1 , ... , c N + n > 0. We prove that for every matrix A ∈ M n (C) satisfying ‖ A ‖ < R , ‖ f (A) ‖ = f (‖ A ‖) ⟺ ‖ A ‖ ∈ σ (A) , where σ (A) is the spectrum of A. Consequently, this resolves a conjecture of Bünger and Rump in [2]. [ABSTRACT FROM AUTHOR] |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.laa.2026.07.011 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 9 StartPage: 154 Subjects: – SubjectFull: Matrix functions Type: general – SubjectFull: Matrix norms Type: general – SubjectFull: Matrix inequalities Type: general – SubjectFull: Operator functions Type: general – SubjectFull: Mathematical equivalence Type: general – SubjectFull: Spectral theory Type: general Titles: – TitleFull: The equality case in ‖f(A)‖ ≤ f(‖A‖) for analytic matrix functions under strongly stable norms. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Zhang, Teng IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 12 Text: Dec2026 Type: published Y: 2026 Identifiers: – Type: issn-print Value: 00243795 Numbering: – Type: volume Value: 750 Titles: – TitleFull: Linear Algebra & its Applications Type: main |
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