English

No metrics with Positive Scalar Curvatures on Aspherical 5-Manifolds

Differential Geometry 2020-09-14 v1 Metric Geometry

Abstract

A metric space XX is called uniformly acyclic if there there exists an {\it acyclicty control function} R=R(r)=RX(r)rR=R(r)=R_X(r)\geq r , 0r<0\leq r <\infty, such that the homology inclusion homomorphisms between the balls around all points xXx\in X, Hi(Bx(r))Hi(Bx(R))H_i(B_x(r))\to H_i(B_x(R)) vanish for all i=1,2,i=1,2,\ldots. We show that if a complete orientable mm-dimensional manifold X~\tilde X of dimension m5m\leq 5 admits a proper (infinity goes to infinity) distance decreasing map to a complete mm-dimensional uniformly acyclic manifold, then the scalar curvature of X~\tilde X can't be uniformly positive, infxX~Sc(X,x)0.\inf _{x\in \tilde X}Sc(X,x) \leq 0. Since the universal coverings X~\tilde X of compact aspherical manifolds XX are {\it uniformly acyclic}, (in fact, {\it uniformly contractible}), these XX, admit no metrics with Sc>0Sc>0 for dim(X)5dim (X)\leq 5. Our argument, that depends on {\it torical symmetrization} of {\it stable μ\mu-bubbles}, is inspired by the recent paper by Otis Chodosh and Chao Li on non-existence of metrics with Sc>0Sc>0 on aspherical 4-manifolds and is also influenced by the ideas of Jintian Zhu and Thomas Richard.

Keywords

Cite

@article{arxiv.2009.05332,
  title  = {No metrics with Positive Scalar Curvatures on Aspherical 5-Manifolds},
  author = {Misha Gromov},
  journal= {arXiv preprint arXiv:2009.05332},
  year   = {2020}
}