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In this paper, we investigate the geometry and classification of three-dimensional CR Yamabe solitons. In the compact case, we show that any 3-dimensional CR Yamabe soliton must have constant Tanaka-Webster scalar curvature; we also obtain…

Differential Geometry · Mathematics 2015-10-16 Huai-Dong Cao , Shu-Cheng Chang , Chih-Wei Chen

We investigate some effects of the lack of compactness in the critical Sobolev embedding by proving that a famous conjecture of Brezis and Peletier \cite{BP89} does still hold in the Heisenberg framework: optimal functions for a natural…

Analysis of PDEs · Mathematics 2024-05-21 Giampiero Palatucci , Mirco Piccinini

In this paper we study positive solutions to the CR Yamabe equation in noncompact $(2n+1)$-dimensional Sasakian manifolds with nonnegative curvature. In particular, we show that the Heisenberg group $\mathbb{H}^1$ is the only (complete)…

Differential Geometry · Mathematics 2024-12-12 Giovanni Catino , Dario Daniele Monticelli , Alberto Roncoroni , Xiaodong Wang

In this paper, we show that the sub-Laplacian of an asymptotically flat pseudo-hermitian manifold defined on a suitable weighted Folland-Stein spaces is an isomorphism. It turns out that the CR positive mass problem is resolved, and hence…

Differential Geometry · Mathematics 2022-03-21 Hung-Lin Chiu

In the study of the extremal for Sobolev inequality on the Heisenberg group and the Cauchy-Riemann(CR) Yamabe problem, Jerison-Lee found a three-dimensional family of differential identities for critical exponent subelliptic equation on…

Analysis of PDEs · Mathematics 2024-04-22 Xi-Nan Ma , Qianzhong Ou , Tian Wu

In this paper, we concern with the Sasaki analogue of Yau uniformization conjecture in a complete noncompact Sasakian manifold with nonnegative transverse bisectional curvature. As a consequence, we confirm that any $5$-dimensional complete…

Differential Geometry · Mathematics 2026-01-16 Shu-Cheng Chang , Yingbo Han , Chien Lin , Chin-Tung Wu

Let \((M^n,g)\) be a smooth closed Riemannian manifold of dimension \(n \ge 5\) with positive Yamabe invariant and semi-positive \(Q\)-curvature. We establish a precompactness result in the \(C^{\alpha}\)-H\"older topologie on the space of…

Differential Geometry · Mathematics 2026-04-14 Zeinab Mcheik

We reduce to various absolute parallelisms, namely to certain {e}-structures on manifolds of dimensions 7, 6, 5, the biholomorphic equivalence problem or the intrinsic CR equivalence problem for generic submanifolds M^5 in C^4 of CR…

Complex Variables · Mathematics 2014-01-20 Masoud Sabzevari , Joel Merker

A complex filling of a CR manifold is said to be equivariant with respect to a CR action if the action extends to a smooth action by biholomorphisms on the whole filling. Under a noncompactness condition for the action, we describe all…

Differential Geometry · Mathematics 2009-01-05 Benoit Kloeckner

We consider the CR Yamabe equation with critical Sobolev exponent on a closed contact manifold M of dimension 2n + 1. The problem of finding solutions with minimum energy has been resolved for all dimensions except dimension 5 (n = 2). In…

Differential Geometry · Mathematics 2021-07-12 Jih-Hsin Cheng , Hung-Lin Chiu

We initiate the study of an analogue of the Yamabe problem for complex manifolds. More precisely, fixed a conformal Hermitian structure on a compact complex manifold, we are concerned in the existence of metrics with constant Chern scalar…

Differential Geometry · Mathematics 2017-09-05 Daniele Angella , Simone Calamai , Cristiano Spotti

Let $ X $ be an oriented, closed manifold with $ \dim X \geqslant 2 $. Let $ (Z, \partial Z) $ be an oriented, compact manifold with (possibly empty) smooth boundary and $ \dim Z \geqslant 2 $. In this article, we show that if the…

Differential Geometry · Mathematics 2025-09-30 Jie Xu

Applying the equivariant moving frames method, we construct convergent normal forms for real-analytic 5-dimensional totally nondegenerate CR submanifolds of C^4. These CR manifolds are divided into several biholomorphically inequivalent…

Complex Variables · Mathematics 2020-05-08 Masoud Sabzevari

We consider the Yamabe invariant of a compact orbifold with finitely many singular points. We prove a fundamental inequality for the estimate of the invariant from above, which also includes a criterion for the non-positivity of it.…

Differential Geometry · Mathematics 2010-09-21 Kazuo Akutagawa

We prove compactness of solutions of a fully nonlinear Yamabe problem satisfying a lower Ricci curvature bound, when the manifold is not conformally diffeomorphic to the standard sphere. This allows us to prove the existence of solutions…

Analysis of PDEs · Mathematics 2014-10-14 YanYan Li , Luc Nguyen

In this paper, we show that there exists a nonconstant CR holomorphic function of polynomial growth in a complete noncompact Sasakian manifold of nonnegative pseudohermitian bisectional curvature with the CR maximal volume growth property.…

Differential Geometry · Mathematics 2019-09-17 Shu-Cheng Chang , Yingbo Han , Nan Li , Chien Lin

In the first part of this thesis, we study the Yamabe problem with singularities, that we can announce as follow: Given a compact Riemannian manifold $(M,g)$, find a constant scalar curvature metric, conformal to $g$, when $g$ has not…

Differential Geometry · Mathematics 2009-10-07 Farid Madani

We provide a complete resolution to the question of compactness for the full solution sets of the fourth-order and sixth-order constant $Q$-curvature problems on smooth closed Riemannian manifolds not conformally diffeomorphic to the…

Analysis of PDEs · Mathematics 2025-09-22 Liuwei Gong , Seunghyeok Kim , Juncheng Wei

We introduce a sequence of conformally invariant scalar curvature quantities, defined along the conformal infinity of a conformally compact (CC) manifold, that measure the failure of a CC metric to have constant negative scalar curvature in…

Differential Geometry · Mathematics 2025-01-22 A. Rod Gover , Jarosław Kopiński , Andrew Waldron

We classify all compact simply connected homogeneous CR manifolds $M$ of codimension one and with non-degenerate Levi form up to CR equivalence. The classification is based on our previous results and on a description of the maximal…

Differential Geometry · Mathematics 2007-05-23 Dmitry V. Alekseevsky , Andrea F. Spiro