Positive $(p, n)$-intermediate scalar curvature and cobordism

TL;DR

This paper extends known scalar curvature surgery techniques to intermediate scalar curvatures, demonstrating that certain high-dimensional manifolds admit infinitely many distinct positive intermediate scalar curvature metrics.

Contribution

It generalizes the Gromov-Lawson and related constructions to $(p,n)$-intermediate scalar curvature and proves the existence of infinitely many disconnected curvature metrics on specific manifolds.

Findings

Extension of surgery techniques to $(p,n)$-intermediate scalar curvature

Construction of infinitely many disconnected positive curvature metrics

Application to high-dimensional spin manifolds

Abstract

In this paper we consider a well-known construction due to Gromov and Lawson, Schoen and Yau, Gajer, and Walsh which allows for the extension of a metric of positive scalar curvature over the trace of a surgery in codimension at least $3$ to a metric of positive scalar curvature which is a product near the boundary. We generalize this construction to work for $(p,n)$-intermediate scalar curvature for $0\leq p\leq n-2$ for surgeries in codimension at least $p+3$. We then use it to generalize a well known theorem of Carr. Letting ${\cal R}^{s_{p,n}>0}(M)$ denote the space of positive $(p, n)$-intermediate scalar curvature metrics on an $n$-manifold $M$, we show for $0\leq p\leq 2n-3$ and $n\geq 2$, that for a closed, spin, $(4n-1)$-manifold $M$ admitting a metric of positive $(p,4n-1)$-intermediate scalar curvature, ${\cal R}^{s_{p,4n-1}>0}(M)$ has infinitely many path components.