English

On index expectation curvature for manifolds

Differential Geometry 2020-01-22 v1

Abstract

Index expectation curvature K(x) = E[i_f(x)] on a compact Riemannian 2d-manifold M is the expectation of Poincare-Hopf indices i_f(x) and so satisfies the Gauss-Bonnet relation that the interval of K over M is Euler characteristic X(M). Unlike the Gauss-Bonnet-Chern integrand, such curvatures are in general non-local. We show that for small 2d-manifolds M with boundary embedded in a parallelizable 2d-manifold N of definite sectional curvature sign e, an index expectation K(x) with definite sign e^d exists. The function K(x) is constructed as a product of sectional index expectation curvature averages K_k(x) = E[i_k(x)] of a probability space of Morse functions f for which i_f(x) is the product of i_k(x), where the i_k are independent and so uncorrelated.

Cite

@article{arxiv.2001.06925,
  title  = {On index expectation curvature for manifolds},
  author = {Oliver Knill},
  journal= {arXiv preprint arXiv:2001.06925},
  year   = {2020}
}

Comments

13 pages figures

R2 v1 2026-06-23T13:15:13.818Z