Inequalities are established for certain trilinear scalar-valued functionals. These functionals act on measurable functions of one real variable, are defined by integration over two- or three-dimensional spaces, and are controlled in terms of Lebesgue space norms of the functions, and of negative powers of large parameters describing a degree of oscillation. Related sublevel set inequalities are a central element of the analysis.
The main results and the main lines of their proofs are largely unchanged in this draft, but some details have been corrected. The analysis has already been extended in work of the author, Durcik, and Roos.
This paper is devoted to $L^2$ estimates for trilinear oscillatory integrals of convolution type on $\mathbb{R}^2$. The phases in the oscillatory factors include smooth functions and polynomials. We shall establish sharp $L^2$ decay estimates of trilinear oscillatory integrals with smooth phases, and then give $L^2$ uniform estimates for these integrals with polynomial phases.
Lebesgue space inequalities are proved for a variant of the triangular Hilbert transform involving curvature. The analysis relies on a crucial trilinear smoothing inequality developed herein, and on bounds for an anisotropic variant of the twisted paraproduct. The trilinear smoothing inequality also leads to Lebesgue space bounds for a corresponding maximal function and a quantitative nonlinear Roth-type theorem concerning patterns in the Euclidean plane.
In this paper, we prove an $L^2-L^2-L^2$ decay estimate for a trilinear oscillatory integral of convolution type in $\mathbb{R}^d,$ which recovers the earlier result of Li (2013) when $d=1.$ We discuss the sharpness of our result in the $d=2$ case. Our main hypothesis has close connections to the property of simple nondegeneracy studied by Christ, Li, Tao and Thiele (2005).
Sparse Bounds for Oscillatory and Random Singular Integrals
令$ T_{P } f (x) = \int e ^{i P (y)} K (y) f (x-y) \; dy $，其中$ K (y)$是$ \mathbb R ^{n}$上的光滑Calderón-Zygmund核，$ P$是多项式。我们证明了双线性型$ \langle T_P f, g \rangle$存在一个稀疏界。这反过来又容易地暗示$ A_p $不等式。证明的方法应用在一个随机离散设置，产生的第一个加权不等式的运营商定义在稀疏集的整数。
For polynomial $ P (x,y)$, and any Calderón-Zygmund kernel, $K$, the operator below satisfies a $ (1,r)$ sparse bound, for $ 1< r \leq 2$. $$ \sup _{ε>0} \Bigl\lvert \int_{|y| > ε} f (x-y) e ^{2 πi P (x,y) } K(y) \; dy \Bigr\rvert $$ The implied bound depends upon $ P (x,y)$ only through the degree of $ P$. We derive from this a range of weighted inequalities, including weak type inequalities on $ L ^{1} (w)$, which are new, even in the unweighted case. The unweighted weak-type estimate, without maximal truncations, is due to Chanillo and Christ (1987).
We derive Lyapunov-type inequalities for general third order nonlinear equations involving multiple $ψ$-Laplacian operators of the form \begin{equation*} (ψ_{2}((ψ_{1}(u'))'))' + q(x)f(u) = 0, \end{equation*} where $ψ_{2}$ and $ψ_{1}$ are odd, increasing functions, $ψ_{2}$ is super-multiplicative, $ψ_{1}$ is sub-multiplicative, and $\frac{1}{ψ_{1}}$ is convex, and $f$ is a continuous function which satisfies a sign condition. Our results utilize $q_{+}$ and $q_{-}$, as opposed to $|q|$ which appears in most results in the literature. Additionally, these new inequalities generalize previously o…
Sharp variational estimates of Stein-Wainger type operators
Ministry of Education Key Laboratory of NSLSCS, School of Mathematical Sciences and Institute of Mathematical Sciences, Nanjing Normal University（南京师范大学数学科学学院和数学科学研究院）
