TY - JOUR
T1 - Polynomial sequences in discrete nilpotent groups of step 2
AU - Ionescu, Alexandru D.
AU - Magyar, Ákos
AU - Mirek, Mariusz
AU - Szarek, Tomasz Z.
N1 - Funding Information:
Funding information : The first, second and third authors were supported in part by NSF grants DMS-2007008 and DMS-1600840 and DMS-2154712 respectively. The third author was also partially supported by the Department of Mathematics at Rutgers University and by the National Science Centre in Poland, grant Opus 2018/31/B/ST1/00204. The fourth author was partially supported by the National Science Centre of Poland, grant Opus 2017/27/B/ST1/01623, the Juan de la Cierva Incorporación 2019, grant number IJC2019-039661-I, the Agencia Estatal de Investigación, grant PID2020-113156GB-I00/AEI/10.13039/501100011033, the Basque Government through the BERC 2022-2025 program, and by the Spanish Ministry of Sciences, Innovation and Universities: BCAM Severo Ochoa accreditation CEX2021-001142-S.
Publisher Copyright:
© 2023 the author(s), published by De Gruyter.
PY - 2023/1/1
Y1 - 2023/1/1
N2 - We discuss some of our work on averages along polynomial sequences in nilpotent groups of step 2. Our main results include boundedness of associated maximal functions and singular integrals operators, an almost everywhere pointwise convergence theorem for ergodic averages along polynomial sequences, and a nilpotent Waring theorem. Our proofs are based on analytical tools, such as a nilpotent Weyl inequality, and on complex almost-orthogonality arguments that are designed to replace Fourier transform tools, which are not available in the noncommutative nilpotent setting. In particular, we present what we call a nilpotent circle method that allows us to adapt some of the ideas of the classical circle method to the setting of nilpotent groups.
AB - We discuss some of our work on averages along polynomial sequences in nilpotent groups of step 2. Our main results include boundedness of associated maximal functions and singular integrals operators, an almost everywhere pointwise convergence theorem for ergodic averages along polynomial sequences, and a nilpotent Waring theorem. Our proofs are based on analytical tools, such as a nilpotent Weyl inequality, and on complex almost-orthogonality arguments that are designed to replace Fourier transform tools, which are not available in the noncommutative nilpotent setting. In particular, we present what we call a nilpotent circle method that allows us to adapt some of the ideas of the classical circle method to the setting of nilpotent groups.
KW - discrete nilpotent groups
KW - nilpotent circle method
KW - pointwise ergodic theorems
KW - Weyl inequality
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U2 - 10.1515/ans-2023-0085
DO - 10.1515/ans-2023-0085
M3 - Article
AN - SCOPUS:85168265610
SN - 1536-1365
VL - 23
JO - Advanced Nonlinear Studies
JF - Advanced Nonlinear Studies
IS - 1
M1 - 20230085
ER -