Conformal deformations on a noncompact Riemannian manifold

1993 ◽  
Vol 295 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Ma Li
Author(s):  
Nigel Higson ◽  
John Roe ◽  
Guoliang Yu

In [1], [4], and [6] the authors have studied index problems associated with the ‘coarse geometry’ of a metric space, which typically might be a complete noncompact Riemannian manifold or a group equipped with a word metric. The second author has introduced a cohomology theory, coarse cohomology, which is functorial on the category of metric spaces and coarse maps, and which can be computed in many examples. Associated to such a metric space there is also a C*-algebra generated by locally compact operators with finite propagation. In this note we will show that for suitable decompositions of a metric space there are Mayer–Vietoris sequences both in coarse cohomology and in the K-theory of the C*-algebra. As an application we shall calculate the K-theory of the C*-algebra associated to a metric cone. The result is consistent with the calculation of the coarse cohomology of the cone, and with a ‘coarse’ version of the Baum–Connes conjecture.


2008 ◽  
Vol 60 (6) ◽  
pp. 1201-1218 ◽  
Author(s):  
Eric Bahuaud ◽  
Tracey Marsh

AbstractWe consider a complete noncompact Riemannian manifold M and give conditions on a compact submanifold K ⊂ M so that the outward normal exponential map off the boundary of K is a diffeomorphism onto M\K. We use this to compactify M and show that pinched negative sectional curvature outside K implies M has a compactification with a well-defined Hölder structure independent of K. The Hölder constant depends on the ratio of the curvature pinching. This extends and generalizes a 1985 result of Anderson and Schoen.


2009 ◽  
Vol 2009 ◽  
pp. 1-20 ◽  
Author(s):  
M. Enstedt ◽  
M. Melgaard

We establish existence of infinitely many distinct solutions to the semilinear elliptic Hartree-Fock equations forN-electron Coulomb systems with quasirelativistic kinetic energy−α−2Δxn+α−4−α−2for thenthelectron. Moreover, we prove existence of a ground state. The results are valid under the hypotheses that the total chargeZtotofKnuclei is greater thanN−1and thatZtotis smaller than a critical chargeZc. The proofs are based on a new application of the Fang-Ghoussoub critical point approach to multiple solutions on a noncompact Riemannian manifold, in combination with density operator techniques.


2018 ◽  
Vol 2020 (21) ◽  
pp. 7857-7872
Author(s):  
Xiaosong Kang ◽  
Xu Xu ◽  
Dunmu Zhang

Abstract We give some conditions for a complete noncompact Riemannian manifold with lower quadratic curvature decay to have finite topological type. Most of our curvature conditions are much weaker than the assumptions in Lott [5] and in Sha–Shen [10], hence our results can be viewed as natural generalizations of those works.


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