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pro vyhledávání: '"Thomas Ransford"'
The Dirichlet space is one of the three fundamental Hilbert spaces of holomorphic functions on the unit disk. It boasts a rich and beautiful theory, yet at the same time remains a source of challenging open problems and a subject of active mathematic
Publikováno v:
Bulletin of the London Mathematical Society. 54:1120-1130
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::cea1275125085ca2732c1280bc84adc7
https://doi.org/10.1112/blms.12618
https://doi.org/10.1112/blms.12618
Publikováno v:
Integral Equations and Operator Theory. 94
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_________::0afed85803ef2ec877fe37d8f1d55dca
https://doi.org/10.1007/s00020-022-02698-0
https://doi.org/10.1007/s00020-022-02698-0
Autor:
Kelly Bickel, Elias Wegert, Felix L. Schwenninger, Thomas Ransford, Pamela Gorkin, Anne Greenbaum
Publikováno v:
Computational Methods and Function Theory, 20(3-4), 701-728. Springer
In this paper, we establish several results related to Crouzeix's conjecture. We show that the conjecture holds for contractions with eigenvalues that are sufficiently well-separated. This separation is measured by the so-called separation constant,
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::76bf230ad9334407850d1a0c3666bc7e
https://doi.org/10.1007/s40315-020-00350-9
https://doi.org/10.1007/s40315-020-00350-9
Using some extensions of a theorem of Heppes on finitely supported discrete probability measures, we address the problems of classification and testing based on projections. In particular, when the support of the distributions is known in advance (as
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::0f4efe2069a70b96d829d2f7829790ca
http://arxiv.org/abs/2201.07628
http://arxiv.org/abs/2201.07628
Autor:
Thomas Ransford, Nathan Walsh
Publikováno v:
Journal of Mathematical Analysis and Applications. 517:126626
We compute the operator norm of real-quadratic polynomials of the Volterra operator. This is used to test whether the Crouzeix conjecture holds for the Volterra operator.
14 pages, 8 figures
14 pages, 8 figures
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::918a723dd35456fbdbb875aba9c00d56
https://doi.org/10.1016/j.jmaa.2022.126626
https://doi.org/10.1016/j.jmaa.2022.126626
Autor:
Thomas Ransford
Potential theory is the broad area of mathematical analysis encompassing such topics as harmonic and subharmonic functions, the Dirichlet problem, harmonic measure, Green's functions, potentials and capacity. This is an introduction to the subject su
Autor:
Javad Mashreghi, Thomas Ransford
We show that if $u$ is a compactly supported distribution on the complex plane such that, for every pair of entire functions $f,g$, \[ \langle u,f\overline{g}\rangle=\langle u,f\rangle\langle u,\overline{g}\rangle, \] then $u$ is supported at a singl
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::24145063e642e0c2a9b2c9e3e4de90f5
http://arxiv.org/abs/2108.01185
http://arxiv.org/abs/2108.01185
Publikováno v:
Journal d'Analyse Mathématique. 138:23-47
Consider the Dirichlet-type space on the bidisk consisting of holomorphic functions $$f(z_1,z_2):=\sum_{k,l\geq0}a_{kl}z_1^kz_2^l$$ such that $$\sum_{^{k,l\geq0}}(k+1)^{\alpha_1}(l+1)^{\alpha_2}|a_{kl}|^{2}
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::babeb392929e25bfdfba1e1ebd2153f4
https://doi.org/10.1007/s11854-019-0014-x
https://doi.org/10.1007/s11854-019-0014-x
Autor:
Javad Mashreghi, Thomas Ransford
Publikováno v:
Studia Mathematica. 244:99-107
We show that, for many holomorphic function spaces on the unit disk, a continuous endomorphism that sends inner functions to inner functions is necessarily a weighted composition operator.
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::33b0ac37d27ac261f159280144528393
https://doi.org/10.4064/sm170724-13-12
https://doi.org/10.4064/sm170724-13-12