We discuss an extension of Toeplitz quantization based on polyanalytic functions. We derive isomorphism theorem for polyanalytic Toeplitz operators between weighted Sobolev-Fock spaces of polyanalytic functions, which...
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We discuss an extension of Toeplitz quantization based on polyanalytic functions. We derive isomorphism theorem for polyanalytic Toeplitz operators between weighted Sobolev-Fock spaces of polyanalytic functions, which are images of modulation spaces under polyanalytic Bargmann transforms. This generalizes well-known results from the analytic setting. Finally, we derive an asymptotic symbol calculus and present an asymptotic expansion of complex Weyl operators in terms of polyanalytic Toeplitz operators.
In 1990, van Eijndhoven and Meyers provide a special orthonormal basis for the Bargmann Hilbert space consisting of holomorphic Hermite functions. Then it was be natural to look for its orthogonal complement in the un...
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In 1990, van Eijndhoven and Meyers provide a special orthonormal basis for the Bargmann Hilbert space consisting of holomorphic Hermite functions. Then it was be natural to look for its orthogonal complement in the underlying -Hilbert space. In this paper, we describe the orthogonal complement of this Hilbert space. More precisely, a polyanalytic orthonormal basis is given and the explicit expressions of the corresponding reproducing kernel functions and Segal-Bargmann integral transforms are provided. The obtained basis are then used to provide a non-trivial - and -fractional like-Fourier transforms.
This work is devoted to the class of sets in the complex plane which nowadays are known as Carathéodory sets, more precisely speaking, as Carathéodory domains and Carathéodory compact sets. These sets n...
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ISBN:
(数字)9783985475728
ISBN:
(纸本)9783985470723
This work is devoted to the class of sets in the complex plane which nowadays are known as Carathéodory sets, more precisely speaking, as Carathéodory domains and Carathéodory compact sets. These sets naturally arose many times in various research areas in Real, Complex and Functional Analysis and in the Theory of Partial Differential Equations. For instance, the concept of a Carathéodory set plays a significant role in such topical themes as approximation in the complex plane, the theory of conformal mappings, boundary value problems for elliptic partial differential equations, etc. The first appearance of Carathéodory domains in the mathematical literature (of course, without the special name at that moment) was at the beginning of the 20th century, when C. Carathéodory published his famous series of papers about boundary behavior of conformal mappings. The next breakthrough result which was obtained with the essential help of this concept is the Walsh–Lebesgue criterion for uniform approximation of functions by harmonic polynomials on plane compacta (1929). Up to now the studies of Carathéodory domains and Carathéodory compact sets remains a topical field of contemporary analysis and a number of important results were recently obtained in this direction. Among them one ought to mention the results about polyanalytic polynomial approximation, where the class of Carathéodory compact sets was one of the crucial tools, and the results about boundary behavior of conformal mappings from the unit disk onto Carathéodory domains. Our aim in the present paper is to give a survey on known results related with Carathéodory sets and to present several new results concerning the matter. Starting with the classical works of Carathéodory, Farrell, Walsh, and passing through the history of Complex Analysis of the 20th century, we come to recently obtained results, and to our contribution to the theory.
We study the fixed points of the Berezin transform in polyanalytic Fock spaces of C-d, d is an element of N*. We show that an L-p function, p is an element of [1, + infinity], with respect to the Lebesgue measure is i...
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We study the fixed points of the Berezin transform in polyanalytic Fock spaces of C-d, d is an element of N*. We show that an L-p function, p is an element of [1, + infinity], with respect to the Lebesgue measure is invariant under this transformation if and only if it is harmonic. From this we deduce that the only bounded fixed points of the Berezin transform of polyanalytic Fock spaces are constant functions. (C) 2019 Elsevier Inc. All rights reserved.
We obtain estimates for the L-p-norm of the short-time Fourier transform (STFT) for functions in modulation spaces, providing information about the concentration on a given subset of R-2, leading to deterministic guar...
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We obtain estimates for the L-p-norm of the short-time Fourier transform (STFT) for functions in modulation spaces, providing information about the concentration on a given subset of R-2, leading to deterministic guarantees for perfect reconstruction using convex optimization methods. More precisely, we obtain large sieve inequalities of the Donoho-Logan type, but instead of localizing the signals in regions T x W of the time-frequency plane using the Fourier transform to intertwine time and frequency, we localize the representation of the signals in terms of the short-time Fourier transform in sets Delta with arbitrary geometry. At the technical level, since there is no proper analogue of Beurling's extremal function in the STFT setting, we introduce a new method, which rests on a combination of an argument similar to Schur's test with an extension of Seip's local reproducing formula to general Hermite windows. When the windows are Hermite functions, we obtain local reproducing formulas for polyanalytic Fock spaces which lead to explicit large sieve constant estimates and, as a byproduct, to a reconstruction formula for f is an element of L-2 (R) from its STFT values on arbitrary discs. (C) 2021 Published by Elsevier Masson SAS.
We discuss some algebraic and analytic properties of a general class of orthogonal polyanalytic polynomials, including their operational formulas, recurrence relations, generating functions, integral representations a...
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We discuss some algebraic and analytic properties of a general class of orthogonal polyanalytic polynomials, including their operational formulas, recurrence relations, generating functions, integral representations and different orthogonality identities. We establish their connection and rule in describing the L-2-spectral theory of some special second order differential operators of Laplacian type acting on the L-2-Gaussian Hilbert space on the whole complex plane. We will also show their importance in the theory of the so-called rank-one automorphic functions on the complex plane. In fact, a variant subclass leads to an orthogonal basis of the corresponding L-2-Gaussian Hilbert space on the strip C/Z.
Let Omega subset of C be a domain and let f (z) = a(z) + (z) over barb(z), where a, b are holomorphic for z is an element of Omega. Denote by. the set of points in Omega at which vertical bar f vertical bar| attains w...
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Let Omega subset of C be a domain and let f (z) = a(z) + (z) over barb(z), where a, b are holomorphic for z is an element of Omega. Denote by. the set of points in Omega at which vertical bar f vertical bar| attains weak local maximum and denote by Sigma the set of points in Omega at which vertical bar f vertical bar attains strict local maximum. We prove that for each p is an element of Lambda \ Sigma, Furthermore, if there is a real analytic curve kappa : I Lambda\ Sigma ( where I is an open real interval), if a, b are complex polynomials, and if f o kappa has a complex polynomial extension, then either f is constant or kappa has constant curvature.
A positive answer is given to the question on the existence of a Nevanlinna contour of Hausdorff dimension exceeding 1, posed by K. Yu. Fedorovskii in 2001. In particular, it is shown that this dimension may exceed 3/2.
A positive answer is given to the question on the existence of a Nevanlinna contour of Hausdorff dimension exceeding 1, posed by K. Yu. Fedorovskii in 2001. In particular, it is shown that this dimension may exceed 3/2.
In this paper we prove that the higher order Lipschitz classes behave invariant under the action of a singular integral operator naturally arising in polyanalytic function theory. This result provides a generalization...
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In this paper we prove that the higher order Lipschitz classes behave invariant under the action of a singular integral operator naturally arising in polyanalytic function theory. This result provides a generalization of the well-known theorem by Joseph Plemelj [16] and Ivan Privalov [17]. (C) 2018 Elsevier Inc. All rights reserved.
For an open set V C Cn, denote by Mα (V) the family of α-analytic functions that obey a boundary maximum modulus principle. We prove that, on a bounded "harmonically fat" domain Ω C Cn, a function f ∈M a(Ω/...
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For an open set V C Cn, denote by Mα (V) the family of α-analytic functions that obey a boundary maximum modulus principle. We prove that, on a bounded "harmonically fat" domain Ω C Cn, a function f ∈M a(Ω/f-1(0)) automatically sat- isfies f ∈M a(Ω), if it is Caj-1smooth in the z/variable, α ∈ Zn+ up to the boundary. For a submanifold U C Cn, denote by ma(U), the set of functions locally approximable by α-analytic functions where each approximating member and its reciprocal (off the singularities) obey the boundary maximum modulus principle. We prove, that for a C3-smooth hypersurface, Ω, a member of ma (Ω), cannot have constant modulus near a point where the Levi form has a positive eigenvalue, unless it is there the trace of a polyanalytic function of a simple form. The result can be partially generalized to C4-smooth submanifolds of higher codimension, at least near points with a Levi cone condition.
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