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The Ricci flow on the 2-sphere with marked points is shown to converge in all three stable, semi-stable, and unstable cases. In the stable case, the flow was known to converge without any reparametrization, and a new proof of this fact is…

Differential Geometry · Mathematics 2014-07-07 D. H. Phong , Jian Song , Jacob Sturm , Xiaowei Wang

We study $n$-dimensional Ricci flows with non-negative Ricci curvature where the curvature is pointwise controlled by the scalar curvature and bounded by $C/t$, starting at metric cones which are Reifenberg outside the tip. We show that any…

Differential Geometry · Mathematics 2024-03-19 Alix Deruelle , Felix Schulze , Miles Simon

We elaborate on nonmetric geometric flow theory and metric-affine gravity with applications in modern cosmology. Two main motivations for our research follow from the facts that 1) cosmological models for $f(Q)$ modified gravity theories,…

General Relativity and Quantum Cosmology · Physics 2024-10-08 L. Bubuianu , E. Nurlan , J. O. Seti , S. Vacaru , E. V. Veliev

The paper intends to offer a general overview on what the concept of integrability means for a nonlinear dynamical system and how the symmetry method can be applied for approaching it. After a general part where key problems as direct and…

Mathematical Physics · Physics 2011-11-08 Rodica Cimpoiasu , Radu Constantinescu

We study geodesics flows on curved quantum Riemannian geometries using a recent formulation in terms of bimodule connections and completely positive maps. We complete this formalism with a canonical $*$ operation on noncommutative vector…

Quantum Algebra · Mathematics 2023-07-12 Edwin Beggs , Shahn Majid

Using double 2+2 and 3+1 nonholonomic fibrations on Lorentz manifolds, we extend the concept of W-entropy for gravitational fields in the general relativity, GR, theory. Such F- and W-functionals were introduced in the Ricci flow theory of…

General Relativity and Quantum Cosmology · Physics 2017-03-28 Vyacheslav Ruchin , Olivia Vacaru , Sergiu I. Vacaru

By studying the weak closure of multidimensional off-diagonal self-joinings we provide a criterion for non-isomorphism of a flow with its inverse, hence the non-reversibility of a flow. This is applied to special flows over rigid…

Dynamical Systems · Mathematics 2014-05-13 K. Fraczek , J. Kulaga , M. Lemanczyk

We establish a structure result for the isometry group of non-compact, homogeneous manifolds admitting an immortal homogeneous Ricci flow solution.

Differential Geometry · Mathematics 2024-05-21 Roberto Araujo

In this work, we study metrics which are both homogeneous and Ricci soliton. If there exists a transitive solvable group of isometries on a Ricci soliton, we show that it is isometric to a solvsoliton. Moreover, unless the manifold is flat,…

Differential Geometry · Mathematics 2013-04-26 Michael Jablonski

We review analytical solutions of the Einstein equations which are expressed in terms of elementary functions and describe Friedmann-Lema\^itre-Robertson-Walker universes sourced by multiple (real or effective) perfect fluids with constant…

General Relativity and Quantum Cosmology · Physics 2021-12-15 Valerio Faraoni , Sonia Jose , Steve Dussault

We show that a flow (timelike congruence) in any type $B_{1}$ warped product spacetime is uniquely and algorithmically determined by the condition of zero flux. (Though restricted, these spaces include many cases of interest.) The flow is…

General Relativity and Quantum Cosmology · Physics 2011-02-01 Mustapha Ishak , Kayll Lake

We consider Ricci flow on two classes of nilpotent Lie groups that generalize the three-dimensional Heisenberg group: the higher-dimensional classical Heisenberg groups, and the groups of real unitriangular matrices. Each group is known to…

Differential Geometry · Mathematics 2014-02-03 Michael Bradford Williams

Ricci solitons are natural generalizations of Einstein metrics. They are also special solutions to Hamilton's Ricci flow and play important roles in the singularity study of the Ricci flow. In this paper, we survey some of the recent…

Differential Geometry · Mathematics 2022-03-29 Huai-Dong Cao

In this work, we obtain some existence results of Chern-Ricci Flows and the corresponding Potential Flows on complex manifolds with possibly incomplete initial data. We discuss the behaviour of the solution as $t\rightarrow 0$. These…

Differential Geometry · Mathematics 2019-08-16 Shaochuang Huang , Man-Chun Lee , Luen-Fai Tam

We build an infinite class of exact axisymmetric solutions of a metric-affine gravity theory, namely, Eddington-inspired Born-Infeld gravity, coupled to an anisotropic fluid as a matter source. The solution-generating method employed is not…

General Relativity and Quantum Cosmology · Physics 2022-03-30 Victor I. Afonso , Gerardo Mora-Pérez , Gonzalo J. Olmo , Emanuele Orazi , Diego Rubiera-Garcia

We develop a theory of Ricci flow for metrics on Courant algebroids which unifies and extends the analytic theory of various geometric flows, yielding a general tool for constructing solutions to supergravity equations. We prove short time…

Differential Geometry · Mathematics 2024-02-20 Jeffrey Streets , Charles Strickland-Constable , Fridrich Valach

In this paper we introduce and study a new kind of hyperbolic geometric flows --dissipative hyperbolic geometric flow. This kind of flow is defined by a system of quasilinear wave equations with dissipative terms. Some interesting exact…

Differential Geometry · Mathematics 2007-09-18 Wen-Rong Dai , De-Xing Kong , Kefeng Liu

Rigidly rotating stationary matter in general relativity has been investigated by Kramer by the Ernst coordinate method. A weakness of this approach is that the Ernst potential does not exist for differential rotation. We now generalize the…

General Relativity and Quantum Cosmology · Physics 2016-08-15 Mattias Marklund , Gyula Fodor , Zoltán Perjés

Hamilton's Ricci flow (RF) equations were recently expressed in terms of a sparsely-coupled system of autonomous first-order nonlinear differential equations for the edge lengths of a d-dimensional piecewise linear (PL) simplicial geometry.…

Differential Geometry · Mathematics 2017-09-26 Paul M. Alsing , Warner A. Miller , Shing-Tung Yau

We expand previous work on an inverse approach to Einstein Field Equations where we include fluids with energy flux and consider the vanishing of the anisotropic stress tensor. We consider the approach using warped product spacetimes of…

General Relativity and Quantum Cosmology · Physics 2011-02-01 James Richardson , Mustapha Ishak