Seppo Hassi

University of Vaasa — Finland

Mathematics · Physical Sciences

23h-index2.2kcitations174works0.92yr avg
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Research Topics

Spectral Theory in Mathematical Physics(131), Matrix Theory and Algorithms(76), Holomorphic and Operator Theory(70), Advanced Mathematical Modeling in Engineering(29), Differential Equations and Boundary Problems(22)

Publications174 total

On sesquilinear forms for lower semibounded (singular) Sturm–Liouville operators
Journal of Differential Equations·2026Open Access
An extension and refinement of the theorems of Douglas and Sebestyén for unbounded operators
Proceedings of the American Mathematical Society·2026
Representing maps for semibounded forms and their Lebesgue‐type decompositions
Journal of the London Mathematical Society·2025Open Access
Local Spectral Theory for Unbounded Product of Nonnegative Selfadjoint Operators
Complex Analysis and Operator Theory·2025· 1 citedOpen Access
On Sesquilinear Forms for Lower Semibounded (Singular) Sturm-Liouville Operators
arXiv (Cornell University)·2025Open Access
Product of nonnegative selfadjoint operators in unbounded settings
ArXiv.org·2025Open Access
An extension and refinement of the theorems of Douglas and Sebestyén for unbounded operators
arXiv (Cornell University)·2025Open Access
ON SESQUILINEAR FORMS FOR LOWER SEMIBOUNDED (SINGULAR) STURM–LIOUVILLE OPERATORS
SSRN Electronic Journal·2025Open Access
Ando’s Lebesgue-Type Decompositions for Pairs of Positive Operators
Operator theory·2025
Nonorthogonal Hilbert Space Decompositions with Operator Range Spaces and Reproducing Kernel Hilbert Spaces
Operator Theory·2025· 2 cited
Friedrichs and Kreĭn type extensions in terms of representing maps
Annals of Functional Analysis·2024· 1 citedOpen Access
Complementation and Lebesgue‐type decompositions of linear operators and relations
Journal of the London Mathematical Society·2024· 6 citedOpen Access
Sequences of Operators, Monotone in the Sense of Contractive Domination
Complex Analysis and Operator Theory·2024· 2 citedOpen Access
Friedrichs and Kre\uın type extensions in terms of representing maps
arXiv (Cornell University)·2024Open Access
Representing maps for semibounded forms and their Lebesgue type decompositions
arXiv (Cornell University)·2023Open Access
Sequences of operators, monotone in the sense of contractive domination
arXiv (Cornell University)·2023Open Access
Complementation and Lebesgue type decompositions of linear operators and relations
arXiv (Cornell University)·2023Open Access
Lebesgue type decompositions and Radon–Nikodym derivatives for pairs of bounded linear operators
Acta Scientiarum Mathematicarum·2022· 6 citedOpen Access
Generalized boundary triples, II. Some applications of generalized boundary triples and form domain invariant Nevanlinna functions
Mathematische Nachrichten·2022· 8 citedOpen Access
Lebesgue type decompositions and Radon-Nikodym derivatives for pairs of bounded linear operators
arXiv (Cornell University)·2021Open Access
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Frequent Co-authors

Henk de Snoo(30), H. S. V. de Snoo(13), Jussi Behrndt(7), Henrik Winkler(7), Vladimir Derkach(6), M. M. Malamud(6), Volodymyr Derkach(4), Franciszek Hugon Szafraniec(4), Zoltán Sebestyén(4), Adrian Sandovici(4), Rudi Wietsma(3), Yury Arlinskii̇̆(3), Yu. M. Arlinskiĭ(2), Harald Woracek(2), Henk S. V. de Snoo(2), Michael Kaltenbäck(2), Kenneth Nordström(1), Л. Л. Оридорога(1), Vadim Mogilevskii(1), A. Willemsma(1)