2007 Fiscal Year Final Research Report Summary
Functional Analyistic Studies On The Algebra Of Bounded Analytic Functions On A Riemann Surface
| Project/Area Number |
16540132
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Basic analysis
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| Research Institution | Hokkaido University |
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Principal Investigator |
HAYASHI Mikihiro Hokkaido University, Fac. of Sci, Professor (40007828)
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| Co-Investigator(Kenkyū-buntansha) |
NAKAZI Takahiko Hokkaido University, Fac. of Sci., Professor (30002174)
TACHIZAWA Kazuya Hokkaido University, Fac. of Sci., Associate Professor (80227090)
NAGASAKA Yukio Hokkaido University, Fac. of Sci., Professor (50001855)
IZUCHI Keiji Niigata University, Dept. of Math., Professor (80120963)
SEGAWA Shigeo Daido Inst., Dept. of Math., Professor (80105634)
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| Project Period (FY) |
2004 – 2007
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| Keywords | bounded analytic function / maximal ideal space / Riemann surface / pole set / Shilov boundary / Hardy class / composition operator / invariant subspace |
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| Research Abstract |
1. Studies on Riemann surfaces and bounded analytic functions and harmonic functions on them:
In the case that a given Riemann surface is not included openly and homeomorphically in the maximal ideal space of the algebra of all bounded analytic functions, we find a condition on a Riemann surface whose Shilov boundary is totally disconeccted. This result can be applied to the uniqueness theorem of linear extremal problem. Also, we studied the structure of the fibre in the maximal ideal space. In addition, we show that Royden's resolution of a Riemann surface can be constructed by the method of simultaneous analytic continuation of a give family of meromorphic functions.
We studied on relations between the Martin boundary and harmonic functions. We succeeded in a characterization for the existence of Green functions on a infinite-sheeted covering Riemann surface over the Riemann sphere, that is obtained by pasting a pair of sheets along each curve in a given sequence of curves, in terms of the sequence of capacities of curves.
2. Stuies on Hardy classes and the function theory of several variables:
We give the best possible estimate of the norm of cross-commutators of two subnormal operators by means of spectral area, and generalized a former result to the case of p-quasi normal operators.
We give a characterization of weighted Herz space by means of wavelets. Our result correct an error in the result published by Tang-Yang in 2000, and further showed that our system of wavelets form an unconditional basis.
We gave a new type of factorization of an inner function in relation of connected components of the zero of the inner function, which solves a problem posed in a paper published in 2004. We also studies when a linear combination of composition operators is compact for an analytic function space.
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Research Products
(45 results)
