On restricted weak-type constants of Fourier multipliers

We exhibit a large class of symbols m: Rd ! C for which the corresponding Fourier multipliers Tm satisfy the following restricted weak-type estimates: if A Rd has finite Lebesgue measure, then... In particular, this leads to novel sharp estimates for the real and imaginary part of the Beurling-Ahlfo...

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Detalhes bibliográficos
Autor: Osekowski, Adam|||0000-0002-8905-2418
Formato: artículo
Fecha de publicación:2014
País:España
Recursos:Universitat Autònoma de Barcelona
Repositorio:Dipòsit Digital de Documents de la UAB
Idioma:inglés
OAI Identifier:oai:ddd.uab.cat:119038
Acesso em linha:https://ddd.uab.cat/record/119038
https://dx.doi.org/urn:doi:10.5565/PUBLMAT_58214_21
Access Level:acceso abierto
Palavra-chave:Fourier multiplier
Singular integral
Beurling-Ahlfors transform
Martingale
Differential subordination
Descrição
Resumo:We exhibit a large class of symbols m: Rd ! C for which the corresponding Fourier multipliers Tm satisfy the following restricted weak-type estimates: if A Rd has finite Lebesgue measure, then... In particular, this leads to novel sharp estimates for the real and imaginary part of the Beurling-Ahlfors operator on C. The proof rests on probabilistic methods: we exploit a stochastic representation of the multipliers in terms of Lévy processes and appropriate sharp inequalities for differentially subordinated martingales.