English

On the bilinear cone multiplier

Classical Analysis and ODEs 2025-05-20 v1

Abstract

For f,gS(Rn),n3f,g \in \mathscr{S}(\R^n), n\geq 3, consider the bilinear cone multiplier operator defined by TRλ(f,g)(x):=R2nmλ(ξRξn,ηRηn)f^(ξ)g^(η)e2πιx(ξ+η) dξdη,{T}^{\lambda}_{R}(f,g)(x):=\int_{\mathbb{R}^{2n}}m^{\lambda}\left(\frac{\xi'}{R\xi_n},\frac{\eta'}{R\eta_n}\right)\hat{f}(\xi)\hat{g}(\eta)e^{2\pi\iota x\cdot(\xi+\eta)}~d\xi d\eta, where λ>0,R>0\lambda>0, R>0 and mλ(ξRξn,ηRηn)=(1ξ2R2ξn2η2R2ηn2)+λφ(ξn)φ(ηn),m^{\lambda}\left(\frac{\xi'}{R\xi_n},\frac{\eta'}{R\eta_n}\right)=\Big(1-\frac{|\xi'|^2}{R^2\xi^2_n}-\frac{|\eta'|^2}{R^2\eta^2_n}\Big)^{\lambda}_{+}\varphi(\xi_n)\varphi(\eta_n), (ξ,ξn),(η,ηn)Rn1×R(\xi',\xi_n), (\eta',\eta_n)\in\mathbb{R}^{n-1}\times \mathbb{R} and φCc([12,2])\varphi\in C_{c}^{\infty}([\frac{1}{2},2]). We investigate the problem of pointwise almost everywhere convergence of TRλ(f,g)(x){T}^{\lambda}_{R}(f,g)(x) as RR\rightarrow \infty for (f,g)Lp1×Lp2(f,g)\in L^{p_1}\times L^{p_2} for a wide range of exponents p1,p2p_1, p_2 satisfying the H\"{o}lder relation 1p1+1p2=1p\frac{1}{p_1}+\frac{1}{p_2}=\frac{1}{p}. This assertion is proved by establishing suitable weighted L2×L2L1L^{2}\times L^{2}\rightarrow L^{1}--estimates of the maximal bilinear cone multiplier operator Tλ(f,g)(x):=supR>0TRλ(f,g)(x).{T}^{\lambda}_{*}(f,g)(x):=\sup_{R>0}|{T}^{\lambda}_{R}(f,g)(x)|.

Keywords

Cite

@article{arxiv.2505.13108,
  title  = {On the bilinear cone multiplier},
  author = {Saurabh Shrivastava and Kalachand Shuin},
  journal= {arXiv preprint arXiv:2505.13108},
  year   = {2025}
}

Comments

25 pages

R2 v1 2026-07-01T02:21:51.349Z