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Construction of gravitational instantons with non-maximal volume growth via codimension-1 collapse

Willem Adriaan Salm

Abstract

In this paper, we construct families of gravitational instantons of type ALG, ALG*, ALH and ALH* using a gluing construction. Away from a finite set of exceptional points, the metric collapses with bounded curvature to a quotient of $\mathbb{R}^3$ by $\mathbb{Z}_2$ and a lattice of rank one or two. Depending on whether the gravitational instantons are of type ALG/ALG* or ALH/ALH*, there are either two or four exceptional points respectively that are modelled on the Atiyah-Hitchin manifold. The other exceptional points are modelled on the Taub-NUT metric. There are at most four, respectively eight, of these points in each case.

Construction of gravitational instantons with non-maximal volume growth via codimension-1 collapse

Abstract

In this paper, we construct families of gravitational instantons of type ALG, ALG*, ALH and ALH* using a gluing construction. Away from a finite set of exceptional points, the metric collapses with bounded curvature to a quotient of by and a lattice of rank one or two. Depending on whether the gravitational instantons are of type ALG/ALG* or ALH/ALH*, there are either two or four exceptional points respectively that are modelled on the Atiyah-Hitchin manifold. The other exceptional points are modelled on the Taub-NUT metric. There are at most four, respectively eight, of these points in each case.

Paper Structure

This paper contains 12 sections, 29 theorems, 110 equations, 3 figures, 3 tables.

Key Result

Theorem \oldthetheorem

Let $L \subset \mathbb{R}^3$ be a lattice of rank one or two and consider the $\mathbb{Z}_2$ action on $\mathbb{R}^3 / L$ that is induced by the antipodal map on $\mathbb{R}^3$. Let $\{p_i\}$ be a configuration of $n$ distinct points in $(\mathbb{R}^3/L - \operatorname{Fix}(\mathbb{Z}_2))/ \mathbb{Z

Figures (3)

  • Figure 1: The multi-Taub-NUT space retracts to a wedge sum of 2-spheres.
  • Figure 2: The underlying manifold $M_{\mathbb{R}^3, n}$ can be seen as the union of the Atiyah-Hitchin manifold and the Multi-Taub-NUT space.
  • Figure 3: Depiction of the 2-cycles with self-intersection -2 inside $P|_{X} \cup \widetilde{P|_{Y}} \cup \: \mathbb{Z}_2 \cdot \widetilde{P|_{Y}}$. The grey planes depict the boundary between these regions. The dark-blue and green spheres form a basis of $H_2(M_{\mathbb{R}^3,5})$ such that its intersection matrix is the negative Cartan matrix of $D_5$. The light-blue spheres are the $\mathbb{Z}_2$ images of the other spheres.

Theorems & Definitions (56)

  • Theorem \oldthetheorem
  • Proposition \oldthetheorem
  • Proposition \oldthetheorem
  • Theorem \oldthetheorem
  • Proposition \oldthetheorem
  • Remark \oldthetheorem
  • Remark \oldthetheorem
  • Lemma \oldthetheorem
  • Remark \oldthetheorem
  • proof
  • ...and 46 more