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arXiv · 1509.05156

The Cotton tensor and Chern-Simons invariants in dimension $3$: an introduction

Sergiu Moroianu
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Abstract

Chern-Simons invariants of closed oriented Riemannian $3$-manifolds are introduced and studied from the basics. Their first-order variation is the Cotton tensor. The properties of the Cotton tensor: symmetry, conformal covariance, trace- and divergence-freedom, are recovered as corollaries of the Chern-Simons invariant. We prove that the Cotton tensor is the obstruction to local conformal flatness in dimension $3$. Finally we discuss the link between Chern-Simons invariants, the eta invariant, and the central value of the Selberg zeta function. This is a survey paper without original results, based on lecture notes for a doctoral course at the University of Bucharest, March 2014.

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Sergiu Moroianu. 2015-09-17. The Cotton tensor and Chern-Simons invariants in dimension $3$: an introduction. https://arxiv.org/abs/1509.05156

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