Paper · Nov 16, 2022

Four-dimensional complete gradient shrinking Ricci solitons with half positive isotropic curvature

Huai-Dong Cao, Junming Xie

math.DGarXiv:2211.09091v4Math. Z. 305 (2023), no. 2, Paper No. 25, 22 pp
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Abstract

In this paper, we investigate the geometry of 4-dimensional complete gradient shrinking Ricci solitons with half positive isotropic curvature (half PIC) or half nonnegative isotropic curvature. Our first main result is a certain form of curvature estimates for such Ricci shrinkers, including a quadratic curvature lower bound estimate for noncompact ones with half PIC. As a consequence, we obtain a new and more direct proof of the classification result, first observed by Li-Ni-Wang [35], for gradient shrinking Kähler-Ricci solitons of complex dimension two with nonnegative isotropic curvature. Moreover, based on a strong maximum principle argument, we classify 4-dimensional complete gradient shrinking Ricci solitons with half nonnegative isotropic curvature (except the half PIC case). Finally, we treat the half PIC case under an additional assumption on the Ricci tensor.

Comments: 22 pages; added the new Corollary 1.2 and the proofs of Lemma 2.1 and formula (2.14)

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  1. Four-dimensional gradient Ricci solitons with (half) nonnegative isotropic curvature

    Huai-Dong Cao and Junming Xie PDF

    Topics Sphere theorems, 4-manifolds, Kähler geometry · Same authors Huai-Dong Cao, Junming Xie · Shared terms “nonnegative isotropic”, “isotropic curvature”, “half positive”

  2. A note on the classification of four-dimensional gradient steady and expanding Ricci solitons

    Huai-Dong Cao and Junming Xie PDF

    Topics 4-manifolds, Boundaries & non-compact, Ricci solitons · Same authors Huai-Dong Cao, Junming Xie · Shared terms “nonnegative isotropic”, “four dimensional”, “half nonnegative”

  3. Kählerity of complete almost-Kähler gradient shrinking Ricci solitons

    Junming Xie PDF

    Topics Kähler–Ricci solitons, 4-manifolds, Boundaries & non-compact · Same author Junming Xie · Shared terms “gradient shrinking”, “shrinking Ricci”, “complete gradient”

  4. Curvature pinching of asymptotically conical gradient expanding Ricci solitons

    Huai-Dong Cao and Junming Xie PDF

    Topics Sphere theorems, 4-manifolds, Boundaries & non-compact · Same authors Huai-Dong Cao, Junming Xie · Shared terms “isotropic curvature”, “positive isotropic”, “four dimensional”

  5. On Shrinking Ricci solitons with positive isotropic curvature in higher dimensions

    Zhengnan Chen PDF

    Topics Sphere theorems, 4-manifolds, Ricci solitons · Shared terms “isotropic curvature”, “positive isotropic”, “shrinking Ricci”

  6. Curvature estimates for four-dimensional complete gradient expanding Ricci solitons

    Huai-Dong Cao and Tianbo Liu PDF

    Topics 4-manifolds, Ricci solitons · Same author Huai-Dong Cao · Shared terms “dimensional complete”, “complete gradient”, “four dimensional”

  7. On curvature estimates for four-dimensional gradient Ricci solitons

    Huai-Dong Cao PDF

    Topics 4-manifolds, Ricci solitons · Same author Huai-Dong Cao · Shared terms “four dimensional”, “curvature estimates”, “Ricci shrinkers”

  8. Complete gradient expanding Ricci solitons with finite asymptotic scalar curvature ratio

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    Topics Ricci solitons · Same authors Huai-Dong Cao, Junming Xie · Shared terms “complete gradient”, “quadratic”

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Background reading

The guides for the topics of this paper: what each idea is, why it matters, and the papers to read first.

In the guidebook

  1. 11A.11
    Hamilton’s 1982 TheoremBook 11A · The Ricci Flow: Existence and Maximum Principles

    Positive Ricci curvature in dimension 3 flows to a round metric.

  2. 11B.1
    Ricci SolitonsBook 11B · Solitons, Compactness and Singularities

    Self-similar solutions: the Gaussian, cylinders, the cigar and the Bryant soliton.

  3. 12B.2
    The Asymptotic Soliton and Three-Dimensional ShrinkersBook 12B · κ-Solutions and Surgery

    Perelman's Proposition 11.2 proved with Morgan and Tian: the reduced-length bounds on κ-solutions, the limit of rescalings, the equality case, and the classification of shrinking solitons in dimensions two and three.