skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Search for: All records

Creators/Authors contains: "Fragkos, Anastasios"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. We prove that the weak- L p L^{p} norms, and in fact the sparse ( p , 1 ) (p,1) -norms, of the Carleson maximal partial Fourier sum operator are ≲<#comment/> ( p −<#comment/> 1 ) −<#comment/> 1 \lesssim (p-1)^{-1} as p →<#comment/> 1 + p\to 1^+ . This is an improvement on the Carleson-Hunt theorem, where the same upper bound on the growth order is obtained for the restricted weak- L p L^p type norm, and which was the strongest quantitative bound prior to our result. Furthermore, our sparse ( p , 1 ) (p,1) -norms bound imply new and stronger results at the endpoint p = 1 p=1 . In particular, we obtain that the Fourier series of functions from the weighted Arias de Reyna space Q A ∞<#comment/> ( w ) \mathrm {QA}_{\infty }(w) , which contains the weighted Antonov space L log ⁡<#comment/> L log ⁡<#comment/> log ⁡<#comment/> log ⁡<#comment/> L ( T ; w ) L\log L\log \log \log L(\mathbb T; w) , converge almost everywhere whenever w ∈<#comment/> A 1 w\in A_1 . This is an extension of the results of Antonov [Proceedings of the XXWorkshop on Function Theory (Moscow, 1995), 1996, pp. 187–196] and Arias De Reyna, where w w must be Lebesgue measure. The backbone of our treatment is a new, sharply quantified near- L 1 L^1 Carleson embedding theorem for the modulation-invariant wave packet transform. The proof of the Carleson embedding relies on a newly developed smooth multi-frequency decomposition which, near the endpoint p = 1 p=1 , outperforms the abstract Hilbert space approach of past works, including the seminal one by Nazarov, Oberlin and Thiele [Math. Res. Lett. 17 (2010), pp. 529–545]. As a further example of application, we obtain a quantified version of the family of sparse bounds for the bilinear Hilbert transforms due to Culiuc, Ou and the first author. 
    more » « less
    Free, publicly-accessible full text available March 1, 2026