$L^p$ regularity for a class of averaging operators on the Heisenberg group

双线性球极平均函数在海森堡群上

Bilinear spherical maximal function on the Heisenberg group

本文研究了海森堡群上的双线性球极平均函数，推导了单尺度双线性平均算子、完整双线性球极极大算子及双线性空隙极大算子的映射估计，其中完整极大算子的结果是最佳的。

Convex isoperimetric sets in the Heisenberg group

We characterize convex isoperimetric sets in the Heisenberg group endowed with horizontal perimeter. We first prove Sobolev regularity for a certain class of vector fields in the plane with bounded variation, related to the curvature equations. Then, by an approximation-reparameterization argument, we show that the boundary of convex isoperimetric sets is foliated by geodesics of the Carnot-Caratheodory distance.

L^p regularity of averages over curves and bounds for associated maximal operators

We prove that for a finite type curve in $\mathbb R^3$ the maximal operator generated by dilations is bounded on $L^p$ for sufficiently large $p$. We also show the endpoint $L^p \to L^{p}_{1/p}$ regularity result for the averaging operators for large $p$. The proofs make use of a deep result of Thomas Wolff about decompositions of cone multipliers.

Maximum boundary regularity of bounded Hua-harmonic functions on tube domains

In this paper we prove that bounded Hua-harmonic functions on tube domains that satisfy some boundary regularity condition are necessarily pluriharmonic. In doing so, we show that a similar theorem is true on one-dimensional extensions of the Heisenberg group or equivalently on the Siegel upper half-plane.

亚黎曼海森堡群中带边界的子流形

Submanifolds with boundary in sub-Riemannian Heisenberg Groups

本文研究亚黎曼海森堡群中具有内在$C^1$正则性的带边界子流形，给出实例并建立涉及Rumin微分形式积分的斯托克斯定理。

在Heisenberg群中内在图的Plateau问题

Plateau's Problem for intrinsic graphs in the Heisenberg Group

本文利用几何构造，在Heisenberg群H^1中解决内在图的Plateau问题，通过小性条件证明了边界或Lipschitz边界数据的最小性，并应用这些技术获得H-周长最小化者的新的正则性结果。

$L^p$ maximal bound and Sobolev regularity of two-parameter averages over tori

We investigate $L^p$ boundedness of the maximal function defined by the averaging operator $f\to \mathcal{A}_t^s f$ over the two-parameter family of tori $\mathbb{T}_t^{s}:=\{ ( (t+s\cosθ)\cosϕ,\,(t+s\cosθ)\sinϕ,\, s\sinθ): θ, ϕ\in [0,2π) \}$ with $c_0t>s>0$ for some $c_0\in (0,1)$. We prove that the associated (two-parameter) maximal function is bounded on $L^p$ if and only if $p>2$. We also obtain $L^p$--$L^q$ estimates for the local maximal operator on a sharp range of $p,q$. Furthermore, the sharp smoothing estimates are proved including the sharp local smoothing estimates for the operator…

Ahlfors-regular distances on the Heisenberg group without biLipschitz pieces

We show that the Heisenberg group is not minimal in looking down. This answers Problem 11.15 in `Fractured fractals and broken dreams' by David and Semmes, or equivalently, Question 22 and hence also Question 24 in `Thirty-three yes or no questions about mappings, measures, and metrics' by Heinonen and Semmes. The non-minimality of the Heisenberg group is shown by giving an example of an Ahlfors $4$-regular metric space $X$ having big pieces of itself such that no Lipschitz map from a subset of $X$ to the Heisenberg group has image with positive measure, and by providing a Lipschitz map from t…

海森堡群中的 Kakeya 极大不等式

Kakeya maximal inequality in the Heisenberg group

本文在配备 Korányi 距离的海森堡群中定义了 Kakeya 极大函数，利用 Wolff 圆形极大函数定理的变体证明了其 $L^3$ 范数不等式，并由此恢复了海森堡 Kakeya 集 Hausdorff 维度的精确下界。

Flag Hardy spaces and Marcinkiewicz multipliers on the Heisenberg group: an expanded version

Marcinkiewicz multipliers are L^{p} bounded for 1<p<\infty on the Heisenberg group H^{n}\simeqC^{n}\timesR (D. Muller, F. Ricci and E. M. Stein) despite the lack of a two parameter group of automorphic dilations on H^{n}. This lack of dilations underlies the inability of classical one or two parameter Hardy space theory to handle Marcinkiewicz multipliers on H^{n} when 0<p\leq1. We address this deficiency by developing a theory of flag Hardy spaces H_{flag}^{p} on the Heisenberg group, 0<p\leq1, that is in a sense `intermediate' between the classical Hardy spaces H^{p} and the product Hardy sp…

旋转平滑

Rotational smoothing

本文系统研究一类算子的旋转平滑现象，包括k向量空间Riesz势及椭圆算子基本解的卷积，旨在低正则性下解决逆问题。