Results 31 to 40 of about 1,092,358 (155)
Evolution of relative Yamabe constant under Ricci Flow [PDF]
, 2019 Let $W$ be a manifold with boundary $M$ given together with a conformal class $\bar C$ which restricts to a conformal class $C$ on $M$. Then the relative Yamabe constant $Y_{\bar C}(W,M;C)$ is well-defined.
Botvinnik, Boris, Lu, Peng
core +1 more source
PERFECT FLUID SPACETIMES, GRAY’S DECOMPOSITION AND f(R, T)-GRAVITY
Hacettepe Journal of Mathematics and Statistics, 2021 In this paper, first we give the complete classifications of perfect fluid spacetimes under the Gray’s decomposition. Then we investigate the condition under which the Ricci tensor is a conformal Killing tensor in a perfect fluid spacetime.
U. De, Sinem Güler
semanticscholar +1 more source
On distinguished orbits of reductive representations [PDF]
, 2013 Let $G$ be a real reductive Lie group and ${\tau}:G \longrightarrow GL(V)$ be a real reductive representation of $G$ with (restricted) moment map $m_{\ggo}: V-{0} \longrightarrow \ggo$.
Fernández-Culma, Edison Alberto
core +2 more sources
On homogeneous warped product Einstein metrics [PDF]
, 2014 In this article we study homogeneous warped product Einstein metrics and its connections with homogeneous Ricci solitons. We show that homogeneous $(\lambda,n+m)$-Einstein manifolds (which are the bases of homogeneous warped product Einstein metrics) are
Lafuente, Ramiro A.
core +1 more source
Purely Magnetic Spacetimes [PDF]
, 1995 Purely magnetic spacetimes, in which the Riemann tensor satisfies $R_{abcd}u^bu^d=0$ for some unit timelike vector $u^a$, are studied. The algebraic consequences for the Weyl and Ricci tensors are examined in detail and consideration given to the ...
Barry M. Haddow, Misra R. M.
core +3 more sources
Ricci almost solitons on semi‐Riemannian warped products [PDF]
Mathematische Nachrichten, 2017 It is shown that a gradient Ricci almost soliton on a warped product, (Bn×hFm,g,f,λ)$\big (B^n\times _h F^m, g,f,\lambda \big )$ whose potential function f depends on the fiber, is either a Ricci soliton or λ is not constant and the warped product, the ...
V. Borges, K. Tenenblat
semanticscholar +1 more source
Curvature decomposition of G_2 manifolds [PDF]
, 2007 Explicit formulas for the $G_2$-components of the Riemannian curvature tensor on a manifold with a $G_2$ structure are given in terms of Ricci contractions.
Alekseevskiĭ +31 more
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Rational Homology 5-Spheres with Positive Ricci Curvature
, 2002 We prove that for every integer k>1 there is a simply connected rational homology 5-sphere $\scriptstyle{M^5_k}$ with spin such that $\scriptstyle{H_2(M^5_k,\bbz)}$ has order $\scriptstyle{k^2},$ and $\scriptstyle{M^5_k}$ admits a Riemannian metric of ...
Boyer, Charles P., Galicki, Krzysztof
core +2 more sources
Local freedom in the gravitational field
, 1996 In a cosmological context, the electric and magnetic parts of the Weyl tensor, E_{ab} and H_{ab}, represent the locally free curvature - i.e. they are not pointwise determined by the matter fields.
Anderson I M +14 more
core +2 more sources
Isoperimetric inequalities on slabs with applications to cubes and Gaussian slabs
Communications on Pure and Applied Mathematics, EarlyView.Abstract We study isoperimetric inequalities on “slabs”, namely weighted Riemannian manifolds obtained as the product of the uniform measure on a finite length interval with a codimension‐one base. As our two main applications, we consider the case when the base is the flat torus R2/2Z2$\mathbb {R}^2 / 2 \mathbb {Z}^2$ and the standard Gaussian measure
Emanuel Milman
wiley +1 more source