On some properties of a Riemannian space with constant scalar curvature
W. Slósarska, Z. Żekanowski (1972)
Colloquium Mathematicae
Similarity:
W. Slósarska, Z. Żekanowski (1972)
Colloquium Mathematicae
Similarity:
Yaning Wang, Ximin Liu (2014)
Annales Polonici Mathematici
Similarity:
We consider an almost Kenmotsu manifold with the characteristic vector field ξ belonging to the (k,μ)’-nullity distribution and h’ ≠ 0 and we prove that is locally isometric to the Riemannian product of an (n+1)-dimensional manifold of constant sectional curvature -4 and a flat n-dimensional manifold, provided that is ξ-Riemannian-semisymmetric. Moreover, if is a ξ-Riemannian-semisymmetric almost Kenmotsu manifold such that ξ belongs to the (k,μ)-nullity distribution, we prove...
Domenico Perrone (1984)
Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti
Similarity:
In questo lavoro si danno alcuni risultati sugli spettri degli operatori di Laplace per varietà Riemanniane compatte con curvatura scalare positiva e di dimensione . Ad essi si aggiunge una osservazione riguardante la congettura di Yamabe.
Szymon M. Walczak (2006)
Annales Polonici Mathematici
Similarity:
We generalize the concept of warped manifold to Riemannian submersions π: M → B between two compact Riemannian manifolds and in the following way. If f: B → (0,∞) is a smooth function on B which is extended to a function f̂ = f ∘ π constant along the fibres of π then we define a new metric on M by , where and denote the bundles of horizontal and vertical vectors. The manifold obtained that way is called a warped submersion. The function f is called a warping function. We show...
Adam Bobrowski, Radosław Bogucki (2008)
Studia Mathematica
Similarity:
Let be a locally compact Hausdorff space. Let , i = 0,1,...,N, be generators of Feller semigroups in C₀() with related Feller processes and let , i = 0,...,N, be non-negative continuous functions on with . Assume that the closure A of defined on generates a Feller semigroup T(t), t ≥ 0 in C₀(). A natural interpretation of a related Feller process X = X(t), t ≥ 0 is that it evolves according to the following heuristic rules: conditional on being at a point p ∈ , with probability...
Nguyen Ngoc Khanh (2016)
Archivum Mathematicum
Similarity:
In this paper, we consider gradient estimates on complete noncompact Riemannian manifolds for the following general heat equation where is a constant and is a differentiable function defined on . We suppose that the Bakry-Émery curvature and the -dimensional Bakry-Émery curvature are bounded from below, respectively. Then we obtain the gradient estimate of Li-Yau type for the above general heat equation. Our results generalize the work of Huang-Ma ([4]) and Y. Li ([6]), recently. ...
Oihane F. Blanco, Miguel Sánchez, José M. Senovilla (2013)
Journal of the European Mathematical Society
Similarity:
, that is to say, Lorentzian manifolds with vanishing second derivative of the curvature tensor , are characterized by several geometric properties, and explicitly presented. Locally, they are a product where each factor is uniquely determined as follows: is a Riemannian symmetric space and is either a constant-curvature Lorentzian space or a definite type of plane wave generalizing the Cahen–Wallach family. In the proper case (i.e., at some point), the curvature...
I. Assani (2005)
Colloquium Mathematicae
Similarity:
We answer a question of H. Furstenberg on the pointwise convergence of the averages , where U and R are positive operators. We also study the pointwise convergence of the averages when T and S are measure preserving transformations.
Xi Chen, Xinran Tao, Xuejun Wang (2023)
Kybernetika
Similarity:
Complete -moment convergence is much more general than complete convergence and complete moment convergence. In this work, we mainly investigate the complete -moment convergence for weighted sums of widely orthant dependent (WOD, for short) arrays. A general result on Complete -moment convergence is obtained under some suitable conditions, which generalizes the corresponding one in the literature. As an application, we establish the complete consistency for the weighted linear estimator...
Domenico Perrone (1984)
Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni
Similarity:
In questo lavoro si danno alcuni risultati sugli spettri degli operatori di Laplace per varietà Riemanniane compatte con curvatura scalare positiva e di dimensione . Ad essi si aggiunge una osservazione riguardante la congettura di Yamabe.
Ori Parzanchevski (2013)
Annales de l’institut Fourier
Similarity:
We study finite -sets and their tensor product with Riemannian manifolds, and obtain results on isospectral quotients and covers. In particular, we show the following: If is a compact connected Riemannian manifold (or orbifold) whose fundamental group has a finite non-cyclic quotient, then has isospectral non-isometric covers.
Brett Kotschwar, Lei Ni (2009)
Annales scientifiques de l'École Normale Supérieure
Similarity:
In the first part of this paper, we prove local interior and boundary gradient estimates for -harmonic functions on general Riemannian manifolds. With these estimates, following the strategy in recent work of R. Moser, we prove an existence theorem for weak solutions to the level set formulation of the (inverse mean curvature) flow for hypersurfaces in ambient manifolds satisfying a sharp volume growth assumption. In the second part of this paper, we consider two parabolic analogues...
Marina B. Khripunova, Sergey E. Stepanov, Irina I. Tsyganok, Josef Mikeš (2016)
Acta Universitatis Palackianae Olomucensis. Facultas Rerum Naturalium. Mathematica
Similarity:
In Riemannian geometry the prescribed Ricci curvature problem is as follows: given a smooth manifold and a symmetric 2-tensor , construct a metric on whose Ricci tensor equals . In particular, DeTurck and Koiso proved the following celebrated result: the Ricci curvature uniquely determines the Levi-Civita connection on any compact Einstein manifold with non-negative section curvature. In the present paper we generalize the result of DeTurck and Koiso for a Riemannian manifold with...
Larry Kitchens, Charles Swartz (1974)
Colloquium Mathematicae
Similarity:
Hiraku Nozawa, José Ignacio Royo Prieto (2014)
Annales de l’institut Fourier
Similarity:
We show that any transversally complete Riemannian foliation of dimension one on any possibly non-compact manifold is tense; namely, admits a Riemannian metric such that the mean curvature form of is basic. This is a partial generalization of a result of Domínguez, which says that any Riemannian foliation on any compact manifold is tense. Our proof is based on some results of Molino and Sergiescu, and it is simpler than the original proof by Domínguez. As an application, we generalize...
Ralph deLaubenfels (2009)
Studia Mathematica
Similarity:
Suppose A is an injective linear operator on a Banach space that generates a uniformly bounded strongly continuous semigroup . It is shown that generates an -regularized semigroup. Several equivalences for generating a strongly continuous semigroup are given. These are used to generate sufficient conditions on the growth of , on subspaces, for generating a strongly continuous semigroup, and to show that the inverse of -d/dx on the closure of its image in L¹([0,∞)) does not generate...
Sreela Gangopadhyay (1990)
Colloquium Mathematicae
Similarity: