Results 1 to 10 of about 642 (56)
Manifolds with 1/4-pinched flag curvature [PDF]
, 2009 We say that a nonnegatively curved manifold $(M,g)$ has quarter pinched flag curvature if for any two planes which intersect in a line the ratio of their sectional curvature is bounded above by 4.
A. Petrunin +24 more
core +6 more sources
Strongly positive curvature [PDF]
, 2014 We begin a systematic study of a curvature condition (strongly positive curvature) which lies strictly between positive curvature operator and positive sectional curvature, and stems from the work of Thorpe in the 1970s.
Bettiol, Renato G. +1 more
core +1 more source
Notes on Perelman's papers [PDF]
, 2008 These are detailed notes on Perelman's papers "The entropy formula for the Ricci flow and its geometric applications" and "Ricci flow with surgery on three-manifolds".Comment: 216 pages, minor corrections ...
Anderson +33 more
core +3 more sources
Global surfaces of section for Reeb flows in dimension three and beyond
, 2020 We survey some recent developments in the quest for global surfaces of section for Reeb flows in dimension three using methods from Symplectic Topology.
Hryniewicz, Umberto L. +1 more
core +1 more source
Generalized Sums over Histories for Quantum Gravity I. Smooth Conifolds [PDF]
, 1993 This paper proposes to generalize the histories included in Euclidean functional integrals from manifolds to a more general set of compact topological spaces.
Amsterdamski +37 more
core +3 more sources
Bifurcation of periodic solutions to the singular Yamabe problem on spheres [PDF]
, 2015 We obtain uncountably many periodic solutions to the singular Yamabe problem on a round sphere, that blow up along a great circle. These are (complete) constant scalar curvature metrics on the complement of $S^1$ inside $S^m$, $m\geq 5$, that are ...
Bettiol, Renato G. +2 more
core +1 more source
Contact structures and Beltrami fields on the torus and the sphere
, 2021 We present new explicit tight and overtwisted contact structures on the (round) 3-sphere and the (flat) 3-torus for which the ambient metric is weakly compatible.
Peralta-Salas, Daniel, Slobodeanu, Radu
core +1 more source
Topological Signals of Singularities in Ricci Flow [PDF]
, 2017 We implement methods from computational homology to obtain a topological signal of singularity formation in a selection of geometries evolved numerically by Ricci flow.
Alsing, Paul M. +6 more
core +4 more sources
The topology of closed manifolds with quasi-constant sectional curvature [PDF]
, 2019 We prove that closed manifolds admitting a generic metric whose sectional curvature is locally quasi-constant are graphs of space forms. In the more general setting of QC spaces where sets of isotropic points are arbitrary, under suitable positivity ...
Funar, Louis
core +5 more sources
Bubbles on Manifolds with a U(1) Isometry [PDF]
, 2007 We investigate the construction of five-dimensional, three-charge supergravity solutions that only have a rotational U(1) isometry. We show that such solutions can be obtained as warped compactifications with a singular ambi-polar hyper-Kahler base space
A. Saxena +24 more
core +2 more sources