Abstract
We derive asymptotic estimates for the growth of the norm of the deformed Hankel transform on the deformed Hankel–Lipschitz space defined via a generalised modulus of continuity. The established results are similar in nature to the well-known Titchmarsh theorem, which provide a characterization of the square integrable functions satisfying certain Cauchy–Lipschitz condition in terms of an asymptotic estimate for the growth of the norm of their Fourier transform. We also give some necessary conditions in terms of the generalised modulus of continuity for the boundedness of the Dunkl transform of functions in Dunkl–Lipschitz spaces, improving the Hausdorff–Young inequality for the Dunkl transform in this special scenario.
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References
Amri, B., Anker, J.-P., Sifi, M.: Three results in Dunkl analysis. Colloq. Math. 118(1), 299–312 (2010)
Anker, J.-Ph.: An introduction to Dunkl theory and its analytic aspects. In: Analytic, algebraic and geometric aspects of differential equations. Trends in Mathematics, pp. 3–58. Birkhäuser/Springer, Cham (2017)
Bari, N.K., Stechkin, S.B.: Best approximations and differential properties of two conjugate functions. (Russian) Trudy Mosk. Mat. Obshch. 5, 483–522 (1956)
Ben, S., Saïd, Kobayashi, T., Ørsted, B.: Laguerre semigroup and Dunkl operators. Compos. Math. 148(4), 1265–1336 (2012)
Ben Saïd, S., Boubatra, M.A., Sifi, M.: On the deformed Besov-Hankel spaces. Opuscula Math. 40(2), 171–207 (2020)
Ben Saïd, S.: A product formula and a convolution structure for a \(k\)-Hankel transform on \({\mathbb{R} }\). J. Math. Anal. Appl. 463(2), 1132–1146 (2018)
Belkina, E.S., Platonov, S.S.: Equivalence of \(K\)-functionals and moduli of smoothness con- structed by generalized Dunkl translations. Izv. Vyssh. Uchebn. Zaved. Mat. 8, 3–15 (2008); translation in Russian Math. (Iz. VUZ) 52(8), 1–11 (2008)
Blasco, O., Karapetyants, A., Restrepo, J.E.: Holomorphic Hölder-type spaces and composition operators. Math. Method. Appl. Sci. 43(17), 10005–10026 (2020)
Bray, W.O., Pinsky, M.A.: Growth properties of Fourier transforms via moduli of continuity. J. Funct. Anal. 255, 2265–2285 (2008)
Bray, W.O.: Growth and integrability of Fourier transforms on Euclidean space. J. Fourier Anal. Appl. 20, 1234–1256 (2014)
Daher, R., Delgado, J., Ruzhansky, M.: Titchmarsh theorems for Fourier transforms of Hölder-Lipschitz functions on compact homogeneous manifolds. Monatsh Math. 189(1), 23–49 (2019)
Daher, R., Fernandez, A., Restrepo, J.E.: Characterising extended Lipschitz type conditions with moduli of continuity. Res. Math. 76, 125 (2021)
Dunkl, C.F.: Differential-difference operators associated to reflection groups. Trans. Am. Math. Soc. 311, 167–183 (1989)
de Jeu, M.F.E.: The Dunkl transform. Invent. Math. 113, 147–162 (1993)
Dunkl, C.F.: Integral kernels with reflection group invariance. Can. J. Math. 43(6), 1213–1227 (1991)
Dunkl, C.F.: Hankel transforms associated to finite reflection groups. In Proceedings of Special Session on Hypergeometric Functions on Domains of Positivity, Jack Polynomials and Applications (Tampa, 1991). Contemporary Mathematics, vol. 138, pp. 123–138 (1992)
Fernandez, A., Restrepo, J.E., Suragan, D.: Lipschitz and Fourier type conditions with moduli of continuity in rank 1 symmetric spaces. Monatsh, Math (2021)
Gorbachev, D., Tikhonov, S.: Moduli of smoothness and growth properties of Fourier transforms: two-sided estimates. J. Approx. Theory 164(9), 1283–1312 (2012)
Gorbachev, D.V., Ivanov, V.I., Tikhonov, S.Y.: Pitt’s inequalities and uncertainty principle for generalized Fourier transform. Int. Math. Res. Not. IMRN 23, 7179–7200 (2016)
Gorbachev, D.V., Ivanov, V.I., Tikhonov, S.Y.: Positive \(L^p\)-bounded Dunkl-type generalized translation operator and its applications. Constr. Approx. 49(3), 555–605 (2019)
Guseinov, A.I., Mukhtarov, HSh.: Introduction to the theory of nonlinear singular integral equations. Russian) Nauka, Moscow (1980)
Kokilashvili, V., Meskhi, A., Rafeiro, H., Samko, S.: Integral Operators in Non-standard Function Spaces. Volume 1: Variable Exponent Lebesgue and Amalgam Spaces. Birkhäuser/Springer, Basel (2016)
Krovokin, P.P.: Linear Operators and Approximation Theory. International Monographs on Advanced Mathematics and Physics (1960)
Kumar, V., Ruzhansky, M.: \(L^p-L^q\) Boundedness of \((k, a)\)-Fourier multipliers with applications to nonlinear equations. Int. Math. Res. Not. 2023(2), 1073–1093 (2023)
Kumar, M., Kumar, V., Ruzhansky, M.: Titchmarsh theorems on Damek-Ricci spaces via moduli of continuity of higher order. arxiv:2107.13044
Negzaoui, S., Oukili, S.: Modulus of continuity and modulus of smoothness related to the deformed Hankel transform. Res. Math. 76(164), 1–17 (2021)
Platonov, S.S.: The Fourier transform of functions satisfying the Lipschitz condition on rank 1 symmetric spaces. Sib. Math. J. 46(6), 1108–1118 (2005)
Rösler, M.: Generalized Hermite polynomials and the heat equation for Dunkl operators. Commun. Math. Phys. 192, 519–542 (1998)
Samko, N.G.: Singular integral operators in weighted spaces with generalized Hölder condition. Proc. A. Razmadze Math. Inst. 120, 107–134 (1999)
Samko, N.: Weighted Hardy and singular operators in Morrey spaces. J. Math. Anal. Appl. 350(1), 56–72 (2009)
Tikhonov, S.: Best approximation and moduli of smoothness: computation and equivalence theorems. J. Approx. Theory 153(1), 19–39 (2008)
Titchmarsh, E.C.: Introduction to the theory of Fourier Integrals. Oxford University Press, Amen House, London, E.C.4 (1948)
Volosivets, S.S.: Fourier transforms and generalized Lipschitz classes in uniform metric. J. Math. Anal. Appl. 383(2), 344–352 (2011)
Watson, G.N.: A Treatise on the Theory of Bessel Functions. Cambridge University Press, Cambridge (1966)
Younis, M.S.: Fourier transforms of Dini–Lipschitz functions. Int. J. Math. Sci. 9(2), 301–312 (1986)
Acknowledgements
The authors were supported by the FWO Odysseus 1 grant G.0H94.18N: Analysis and Partial Differential Equations, the Methusalem programme of the Ghent University Special Research Fund (BOF) (Grant number 01M01021) and by FWO Senior Research Grant G011522N. MR is also supported by EPSRC grant EP/R003025/2.
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Kumar, V., Restrepo, J.E. & Ruzhansky, M. Asymptotic Estimates for the Growth of Deformed Hankel Transform by Modulus of Continuity. Results Math 79, 22 (2024). https://doi.org/10.1007/s00025-023-02051-w
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DOI: https://doi.org/10.1007/s00025-023-02051-w
Keywords
- Lipschitz type condition
- modulus of continuity
- Dunkl transform
- generalized translation operator
- asymptotic estimate