Mathematics – Differential Geometry
Scientific paper
2010-05-27
Journal of Geometry and Physics (60) 2010 1530-1538
Mathematics
Differential Geometry
14 pages
Scientific paper
10.1016/j.geomphys.2010.05.010
A complete Riemannian manifold $(M, g)$ is a $Y^x_l$-manifold if every unit speed geodesic $\gamma(t)$ originating at $\gamma(0)=x\in M$ satisfies $\gamma(l)=x$ for $0\neq l\in \R$. B\'erard-Bergery proved that if $(M^m,g), m>1$ is a $Y^x_l$-manifold, then $M$ is a closed manifold with finite fundamental group, and the cohomology ring $H^*(M, \Q)$ is generated by one element. We say that $(M,g)$ is a $Y^x$-manifold if for every $\epsilon >0$ there exists $l>\epsilon$ such that for every unit speed geodesic $\gamma(t)$ originating at $x$, the point $\gamma(l)$ is $\epsilon$-close to $x$. We use Low's notion of refocussing Lorentzian space-times to show that if $(M^m, g), m>1$ is a $Y^x$-manifold, then $M$ is a closed manifold with finite fundamental group. As a corollary we get that a Riemannian covering of a $Y^x$-manifold is a $Y^x$-manifold. Another corollary is that if $(M^m,g), m=2,3$ is a $Y^x$-manifold, then $(M, h)$ is a $Y^x_l$-manifold for some metric $h.$
Chernov Vladimir
Kinlaw Paul
Sadykov Rustam R.
No associations
LandOfFree
Topological properties of manifolds admitting a $Y^x$-Riemannian metric does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Topological properties of manifolds admitting a $Y^x$-Riemannian metric, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Topological properties of manifolds admitting a $Y^x$-Riemannian metric will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-192483