## G. Catino - P. Mastrolia - D. D. Monticelli

# Gradient Ricci solitons with vanishing conditions on Weyl

created by catino on 03 Feb 2016

modified on 21 Apr 2016

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BibTeX]

*Accepted Paper*

**Inserted:** 3 feb 2016

**Last Updated:** 21 apr 2016

**Journal:** J. Math. Pures Appl.

**Year:** 2016

**Abstract:**

We classify complete gradient Ricci solitons satisfying a fourth-order vanishing condition on the Weyl tensor, improving previously known results. More precisely, we show that any $n$-dimensional ($n\geq 4$) gradient shrinking Ricci soliton with fourth order divergence-free Weyl tensor is either Einstein, or a finite quotient of $N^{n-k}\times \mathbb{R}^k$, $(k > 0)$, the product of a Einstein manifold $N^{n-k}$ with the Gaussian shrinking soliton $\mathbb{R}^k$. The technique applies also to the steady and expanding cases in all dimensions. In particular, we prove that a three dimensional gradient steady soliton with third order divergence-free Cotton tensor, i.e. with vanishing double divergence of the Bach tensor, is either flat or isometric to the Bryant soliton.

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