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Bradley Lewis Burdick

Publications and source records attributed to Bradley Lewis Burdick.

4 recordsLinked to original sources

Ricci-positive metrics on connected sums of products with arbitrarily many spheres

In this paper we construct Ricci-positive metrics on the connected sum of products of arbitrarily many spheres provided the dimensions of all but one sphere in each summand are at least 3. There are two new technical theorems required to extend previous results on sums of products of two spheres. The first theorem is a gluing construction for Ricci-positive manifolds with corners generalizing a gluing construction of Perelman for Ricci-positive manifolds with boundaries. Our construction gives a sufficient condition for gluing together two Ricci-positive manifolds with corners along isometric faces so that the resulting smooth manifold with boundary will be Ricci-positive and have convex boundary. The second theorem claims that one can deform the boundary of a Ricci-positive Riemannian manifold with convex boundary along a Ricci-positive isotopy while preserving Ricci-positivity and boundary convexity.

math.DG↗

Ricci-Positive Metrics on Connected Sums of Projective Spaces

It is a well known result of Gromov that all manifolds of a given dimension with positive sectional curvature are subject to a universal bound on the sum of their Betti numbers. On the other hand, there is no such bound for manifolds with positive Ricci curvature: indeed, Perelman constructed positive Ricci metrics on arbitrary connected sums of complex projective planes. In this paper, we revisit and extend Perelman's techniques to construct positive Ricci metrics on arbitrary connected sums of complex, quaternionic, and octonionic projective spaces in every dimension.

math.DG↗

A Simplicial Tutte "5"-flow Conjecture

This paper concerns a generalization of nowhere-zero modular q-flows from graphs to simplicial complexes of dimension d greater than 1. A modular q-flow of a simplicial complex is an element of the kernel of the d-th boundary map with coefficients in Z/qZ; it is called nowhere-zero if it is not zero restricted to any of the facets of the complex. Briefly noting connections to other invariants of simplicial complexes, this paper provides a generalization of Tutte's 5-flow conjecture, which claims the universal existence of a 5-flow for all bridgeless graphs. Once phrased, this paper concludes with bounds on what "5" ought to be for simplicial complexes of dimension d: proving a lower bound linear in d and a partial upper bound exponential in d.

math.CO↗