Project description
New geometric techniques advance research on maximal operators
In 1997, Juha Kinnunen proved that maximal operators satisfy Sobolev bounds when the exponent p exceeds 1, igniting widespread research into maximal function regularity. Building on this foundation, recent advances using geometric techniques have achieved significant breakthroughs in higher-dimensional endpoint regularity bounds. Funded by the Marie Skłodowska-Curie Actions programme, the SRMF project leverages these new geometric tools with already established extremisation methods to tackle many open questions in the field. The proposed research aims to demonstrate that the variation in non-centred maximal functions can be regulated by the function variation and address a long-standing open question at p=1. It will also seek to prove that the centred Hardy-Littlewood maximal operator in one dimension does not increase the variation in a function.
Objective
In 1997 Juha Kinnunen proved that maximal operators satisfy a Sobolev bound if the Sobolev exponent p is strictly larger than 1. His article initiated the study of regularity of maximal functions, a field which has attracted several dozens of authors to this day. Geometric techniques have recently lead to a series of breakthrough endpoint regularity bounds for maximal operators in higher dimensions. This project pursues the novel strategy of combining these new geometric tools with already established extremization techniques in order to solve a wide range of open questions in the field.
The goals of the project are organized around two themes: gradient bounds and sharp constants. The main goal from the first theme is to prove that the variation of the non-centered Hardy-Littlewood maximal function can be controlled by the variation of the function in all dimensions. This is the endpoint p=1 of Juha Kinnunen's original bound and is one of the main long standing open questions in the field. This project also aims to prove this variation bound for further maximal operators, along with the operator continuity of their gradient and bounds for higher derivatives.
The main goal from the second theme is to prove that the centered Hardy-Littlewood maximal operator in one dimension does not increase the variation of a function. This bound would be sharp because examples show that in general, maximal operators do not strictly decrease the variation of a function. This project further aims to prove this sharp bound for convolution type maximal operators and to find the sharp constant in the variation bound for the dyadic maximal operator in all dimensions.
Keywords
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Project’s keywords as indicated by the project coordinator. Not to be confused with the EuroSciVoc taxonomy (Fields of science)
Programme(s)
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
Multi-annual funding programmes that define the EU’s priorities for research and innovation.
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HORIZON.1.2 - Marie Skłodowska-Curie Actions (MSCA)
MAIN PROGRAMME
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Topic(s)
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Calls for proposals are divided into topics. A topic defines a specific subject or area for which applicants can submit proposals. The description of a topic comprises its specific scope and the expected impact of the funded project.
Funding Scheme
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Funding scheme (or “Type of Action”) inside a programme with common features. It specifies: the scope of what is funded; the reimbursement rate; specific evaluation criteria to qualify for funding; and the use of simplified forms of costs like lump sums.
HORIZON-TMA-MSCA-PF-EF - HORIZON TMA MSCA Postdoctoral Fellowships - European Fellowships
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Call for proposal
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Procedure for inviting applicants to submit project proposals, with the aim of receiving EU funding.
(opens in new window) HORIZON-MSCA-2023-PF-01
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75007 PARIS
France
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