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In this paper we investigate a kind of generalized Ricci flow which possesses a gradient form. We study the monotonicity of the given function under the generalized Ricci flow and prove that the related system of partial differential…

Differential Geometry · Mathematics 2011-07-19 Chun-lei He , Sen Hu , De-Xing Kong , Kefeng Liu

In this paper we prove a compactness result for Ricci flows with bounded scalar curvature and entropy. It states that given any sequence of such Ricci flows, we can pass to a subsequence that converges to a metric space which is smooth away…

Differential Geometry · Mathematics 2016-05-16 Richard H. Bamler

In this paper we establish new geometric and analytic bounds for Ricci flows, which will form the basis of a compactness, partial regularity and structure theory for Ricci flows in [Bam20a, Bam20b]. The bounds are optimal up to a constant…

Differential Geometry · Mathematics 2021-09-23 Richard H Bamler

We localize the entropy functionals of G. Perelman and generalize his no-local-collapsing theorem and pseudo-locality theorem. Our generalization is technically inspired by further development of Li-Yau estimates along the Ricci flow. It…

Differential Geometry · Mathematics 2020-10-21 Bing Wang

In this paper we present several curvature estimates and convergence results for solutions of the Ricci flow. The curvature estimates depend on smallness of certain local space-time integrals of the norm of the Riemann curvature tensor,…

Differential Geometry · Mathematics 2007-07-17 Rugang Ye

We study monotonic quantities in the context of combined geometric flows. In particular, focusing on Ricci solitons as the ambient space, we consider solutions of the heat type equation integrated over embedded submanifolds evolving by mean…

High Energy Physics - Theory · Physics 2010-02-01 Efstratios Tsatis

We discuss a natural form of Ricci--flow conjugation between two distinct general relativistic data sets given on a compact $n\geq 3$-dimensional manifold $\Sigma$. We establish the existence of the relevant entropy functionals for the…

General Relativity and Quantum Cosmology · Physics 2010-12-15 Mauro Carfora

B List has recently studied a geometric flow whose fixed points correspond to static Ricci flat spacetimes. It is now known that this flow is in fact Ricci flow modulo pullback by a certain diffeomorphism. We use this observation to…

General Relativity and Quantum Cosmology · Physics 2009-02-20 M M Akbar , E Woolgar

Following work of Ecker, we consider a weighted Gibbons-Hawking-York functional on a Riemannian manifold-with-boundary. We compute its variational properties and its time derivative under Perelman's modified Ricci flow. The answer has a…

Differential Geometry · Mathematics 2015-05-28 John Lott

We simplify and improve the curvature estimates in the paper: On the conditions to extend Ricci flow(II). Furthermore, we develop some volume estimates for the Ricci flow with bounded scalar curvature. These estimates can be applied to…

Differential Geometry · Mathematics 2011-09-21 Xiuxiong Chen , Bing Wang

We consider a closed manifold M with a Riemannian metric g(t) evolving in direction -2S(t) where S(t) is a symmetric two-tensor on (M,g(t)). We prove that if S satisfies a certain tensor inequality, then one can construct a forwards and a…

Differential Geometry · Mathematics 2015-10-14 Reto Müller

Ricci flow deforms the Riemannian metric proportionally to the curvature, such that the curvature evolves according to a heat diffusion process and eventually becomes constant everywhere. Ricci flow has demonstrated its great potential by…

Geometric Topology · Mathematics 2014-03-31 Min Zhang , Ren Guo , Wei Zeng , Feng Luo , Shing-Tung Yau , Xianfeng Gu

We present local estimates for solutions to the Ricci flow, without the assumption that the solution has bounded curvature. These estimates lead to a generalisation of one of the pseudolocality results of G.Perelman in dimension two.

Differential Geometry · Mathematics 2014-11-11 Miles Simon

We introduce analogous geometric quantities and prove some geometric and analytic bounds in [Bam20a] to generalized Ricci flow.

Differential Geometry · Mathematics 2023-11-07 Xilun Li

In recent work of Chan-Huang-Lee, it is shown that if a manifold enjoys uniform bounds on (a) the negative part of the scalar curvature, (b) the local entropy, and (c) volume ratios up to a fixed scale, then there exists a Ricci flow for…

Differential Geometry · Mathematics 2025-04-23 Adam Martens

In this article, we establish a monotonicity formula of Hamilton type entropy along Ricci flow on compact surfaces with boundary. We also study the relation between our entropy functional and the $\mathcal{W}$-functional of Perelman type.

Differential Geometry · Mathematics 2021-07-08 Keita Kunikawa , Yohei Sakurai

This paper attempts to construct monotonic entropy functionals for four-dimensional Lorentzian spacetime under physical boundary conditions, as an extension of Perelman's monotonic entropy functionals constructed for three-dimensional…

General Relativity and Quantum Cosmology · Physics 2026-04-17 M. J. Luo

In this paper, we establish Li-Yau-type and Hamilton-type estimates for positive solutions to the heat equation associated with the generalized Ricci flow, under a less stringent curvature condition. Compared with [25] and [35], these…

Differential Geometry · Mathematics 2025-06-06 Juanling Lu , Yu Zheng

In this paper we prove convergence and compactness results for Ricci flows with bounded scalar curvature and entropy. More specifically, we show that Ricci flows with bounded scalar curvature converge smoothly away from a singular set of…

Differential Geometry · Mathematics 2018-02-08 Richard H. Bamler

In this note, we prove some new entropy formula for linear heat equation on static Riemannian manifold with nonnegative Ricci curvature. The results are analogies of Cao and Hamilton's entropies for Ricci flow coupled with heat-type…

Differential Geometry · Mathematics 2022-07-29 Yucheng Ji