Oscillatory integrals related to Carleson's theorem: fractional monomials

Sharp variation-norm estimates for oscillatory integrals related to Carleson's theorem

We prove variation-norm estimates for certain oscillatory integrals related to Carleson's theorem. Bounds for the corresponding maximal operators were first proven by Stein and Wainger. Our estimates are sharp in the range of exponents, up to endpoints. Such variation-norm estimates have applications to discrete analogues and ergodic theory. The proof relies on square function estimates for Schrödinger-like equations due to Lee, Rogers and Seeger. In dimension one, our proof additionally relies on a local smoothing estimate. Though the known endpoint local smoothing estimate by Rogers and Seeg…

Sparse Bounds for Maximal Monomial Oscillatory Hilbert Transforms

For each $ d \geq 2$, the Hilbert transform with a polynomial oscillation as below satisfies a $ (1, r )$ sparse bound, for all $ r>1$ $$ H _{ \ast } f (x) = \sup _{ε} \Bigl\lvert \int_{|y| > ε} f (x-y) \frac { e ^{2 πi y ^d }} y\; dy \Bigr\rvert. $$ This quickly implies weak-type inequalities for the maximal truncations, which hold for $A_1$ weights, but are new even in the case of Lebesgue measure. The unweighted weak-type estimate \emph{without maximal truncations} but with arbitrary polynomials, is due to Chanillo and Christ (1987).

A remark on oscillatory integrals associated with fewnomials

We prove that the $L^2$ bound of an oscillatory integral associated with a polynomial depends only on the number of monomials that this polynomial consists of.

Extensions of the Stein-Tomas theorem

We prove an endpoint version of the Stein-Tomas restriction theorem, for a general class of measures, and with a strengthened Lorentz space estimate. A similar improvement is obtained for Stein's estimate on oscillatory integrals of Carleson-Sjölin-Hörmander type and some spectral projection operators on compact manifolds, and for classes of oscillatory integral operators with one-sided fold singularities.

A Discrete Quadratic Carleson Theorem on $ \ell ^2 $ with a Restricted Supremum

Consider the discrete maximal function acting on $\ell^2(\mathbb Z)$ functions \[ \mathcal{C}_Λ f( n ) := \sup_{ λ\in Λ} \left| \sum_{m \neq 0} f(n-m) \frac{e^{2 πiλm^2}} {m} \right| \] where $Λ\subset [0,1]$. We give sufficient conditions on $Λ$, met by certain kinds of Cantor sets, for this to be a bounded sublinear operator. This result is a discrete analogue of E. M. Stein's integral result, that the maximal operator below is bounded on $L^2(\mathbb R)$. \[ \mathcal{C}_2 f(x):= \sup_{λ\in \mathbb R} \left| \int f(x-y) \frac{e^{2πi λy^2}}{y} \ dy \right|.\] The proof of our result relies he…

A type of oscillatory integral operator and its applications

In this paper, we consider $L^p$- estimate for a class of oscillatory integral operators satisfying the Carleson-Sjölin conditions with further convex and straight assumptions. As applications, the multiplier problem related to a general class of hypersurfaces with nonvanishing Gaussian curvature, local smoothing estimates for the fractional Schrödinger equation and the sharp resolvent estimates outside of the uniform boundedness range are discussed.

二次超曲面上的多项式Carleson算子研究

On Polynomial Carleson operators along quadratic hypersurfaces

本文研究二次超曲面上的多项式Carleson算子，证明其对任意非退化二次型和所有1<p<∞的Lp空间存在先验界，方法适用于任意符号二次型，突破了此前仅正定情形的限制。

Sharp $L^p$ decay estimates for degenerate and singular oscillatory integral operators: Homogeneous polynomial phases

In this paper, we consider the degenerate and singular oscillatory integral operator with a singular kernel which is not a Calderón-Zygmund kernel and satisfies suitable size and derivative conditions related to a real parameter $μ$. For any given homogeneous polynomial phases, except monomial phases, of degreee $n$, we give the range of $p$ for which the sharp decay rate $-\frac{1-μ}{n}$ on $L^2$ spaces can be preserved on $L^p$ spaces.

流形上的振荡积分算子及相关的Kakeya和Nikodym问题

Oscillatory integral operators on manifolds and related Kakeya and Nikodym problems

本文研究了黎曼流形上的Carleson-Sjölin算子，在常截面曲率和Sogge混沌曲率条件下通过不同方法获得了改进的$L^p$界，并作为副产品得到了Nikodym极大函数的新界。

振荡积分与谱簇的尖锐端点多线性估计

Sharp endpoint multilinear estimates for oscillatory integrals and spectral clusters

本文证明了任意分离频率尺度下Carleson–Sjölin振荡积分算子的尖锐k线性L^p估计，并解决了三维闭Riemann流形上Burq–Gérard–Tzvetkov的对数自由端点双线性谱簇估计问题。

A stationary set method for estimating oscillatory integrals

We propose a new method of estimating oscillatory integrals, which we call a stationary set method. We use it to obtain the sharp convergence exponents of Tarry's problems in dimension two for every degree $k\ge 2$. As a consequence, we obtain sharp Fourier extension estimates for a family of monomial surfaces.

Oscillatory integrals with phase functions of positive real powers and asymptotic expansions

As to methods for expanding an oscillatory integral into an asymptotic series with respect to the parameter, the method of stationary phase for the non-degenerate phases and the method of using resolution of singularities for degenerate phases are known. The aim of this paper is to extend the former for degenerate phases with positive real powers without using resolution of singularities. For this aim, we first generalize Fresnel integrals as oscillatory integrals with phase functions of positive real powers. Next, by using this result, we have asymptotic expansions of oscillatory integrals fo…

A Fourier restriction theorem for hypersurfaces which are graphs of certain real polynomials

We will extend the Fourier restriction inequality for quadratic hypersurfaces obtained by Strichartz. We will consider the case where the hypersurface is a graph of a certain real polynomial which is a sum of one-dimensional monomials. It is essential to examine the decay of a one-dimensional oscillatory

Stein-Wainger型算子的锐利变分估计

Sharp variational estimates of Stein-Wainger type operators

本文研究了Stein-Wainger型算子的$r$-变分在$ L^p(\R^n) $中的不等式，证明了其在端点处的锐利性，并解决了Guo-Roos-Yung提出的问题。