English

Best constants in reverse Riesz-type inequalities for analytic and co-analytic projections

Complex Variables 2025-02-04 v3

Abstract

Let P+P_+ be the Riesz's projection operator and let P=IP+P_-= I - P_+. We consider the inequalities of the following form fLp(T)Bp,s(P+fs+Pfs)1sLp(T) \|f\|_{L^p(\mathbb{T})}\leq B_{p,s}\|( |P_ + f | ^s + |P_- f |^s) ^{\frac 1s}\|_{L^p (\mathbb{T})} and prove them with sharp constant Bp,sB_{p,s} for s[p,+)s \in [p',+\infty) and 1<p21<p\leq 2 and p4,p\geq 4, where p:=min{p,pp1}.p':=\min\{p,\frac{p}{p-1}\}.

Keywords

Cite

@article{arxiv.2408.02453,
  title  = {Best constants in reverse Riesz-type inequalities for analytic and co-analytic projections},
  author = {Petar Melentijević},
  journal= {arXiv preprint arXiv:2408.02453},
  year   = {2025}
}

Comments

21 pages; this version has been accepted for publication in Journal of Mathematical Analysis and Applications