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arXiv · 2508.01420

The Space of Dirac-Minimal Metrics is Connected in Dimensions 2 and 4

Bernd Ammann·Mattias Dahl
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Abstract

Let $M$ be a closed connected spin manifold. Index theory provides a topological lower bound on the dimension of the kernel of the Dirac operator which depends on the choice of Riemannian metric. Riemannian metrics for which this bound is attained are called Dirac-minimal. We show that the space of Dirac-minimal metrics on $M$ is connected if $M$ is of dimension 2 or 4.

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Bernd Ammann, Mattias Dahl. 2025-08-02. The Space of Dirac-Minimal Metrics is Connected in Dimensions 2 and 4. https://doi.org/10.3842/sigma.2025.102

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