6 Result(s)
within
Hyun** Koo
Mathematics, general
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Article
Difference of Weighted Composition Operators Over the Ball
Recently, Choe et al. obtained characterizations for bounded/compact differences of weighted composition operators acting from a standard weighted Bergman space into another over the unit disk. In this paper w...
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Article
Sums of Polyanalytic Dual Toeplitz Products
On the setting of the orthogonal complement of the polyanalytic Bergman space of the unit disk, we give characterizations of when a sum of products of several dual Toeplitz operators is compact or zero. Our re...
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Article
Local Hopf Lemma for Certain Degenerate Elliptic Operators on the Half-Space
We prove that the local Hopf lemma of Baouendi–Rothschild for harmonic functions continues to hold for the degenerate elliptic operator, $$\ma...
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Article
Evolution of the Steklov eigenvalue under geodesic curvature flow
On a two-dimensional compact Riemannian manifold with boundary, we prove that the first nonzero Steklov eigenvalue is nondecreasing along the unnormalized geodesic curvature flow if the initial metric has posi...
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Article
Compact linear combinations of composition operators induced by linear fractional maps
It has been known that the difference of two composition operators induced by linear fractional self-maps of a ball cannot be nontrivially compact on either the Hardy space or any standard weighted Bergman spa...
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Article
Hilbert–Schmidt differences of composition operators on the Bergman space
In the setting of the weighted Bergman space over the unit disk, we characterize Hilbert–Schmidt differences of two composition operators in terms of integrability condition involving pseudohyperbolic distance...
