Paper · Oct 7, 2025

On curvature estimates for four-dimensional gradient Ricci solitons

Huai-Dong Cao

math.DGarXiv:2510.06059Mat. Contemp. 49 (2022), 87-139
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Abstract

In this survey paper, we analyse and compare the recent curvature estimates for three types of -dimensional gradient Ricci solitons, especially between Ricci shrinkers [58] and expanders [17]. In addition, we provide some new curvature estimates for -dimensional gradient steady Ricci solitons, including the sharp curvature estimate for gradient steady Ricci solitons with positive Ricci curvature (see Theorem 1.1).

Comments: 32 pages

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Connected papers

The 8 papers on this site closest to this one, judged by the topics they share, the words and phrases in their titles and abstracts, and their authors. They are not its citations, but a map of the work around it. Papers here go back to 2021, plus the canon.

Connected papers This paper in the centre and the 8 papers closest to it around it, in date order clockwise from the top. The closer a paper sits to the centre, the stronger the connection. This paper Curvature estimates for four-dimensional complete gradient expanding Ricci solitons (Huai-Dong Cao and Tianbo Liu, 2021)3Cao 2021 On Euler characteristic and Hitchin-Thorpe inequality for four-dimensional compact Ricci solitons (Xu Cheng, Ernani Ribeiro and Detang Zhou, 2022)8Cheng 2022 Four-dimensional complete gradient shrinking Ricci solitons with half positive isotropic curvature (Huai-Dong Cao and Junming Xie, 2022)6Cao 2022 Four-dimensional gradient Ricci solitons with (half) nonnegative isotropic curvature (Huai-Dong Cao and Junming Xie, 2024)2Cao 2024 Correction to: Curvature growth of some 4-dimensional gradient Ricci soliton singularity models (Bennett Chow, Michael H. Freedman, Henry Shin et al., 2025)7Chow 2025 Curvature pinching of asymptotically conical gradient expanding Ricci solitons (Huai-Dong Cao and Junming Xie, 2025)5Cao 2025 A note on the classification of four-dimensional gradient steady and expanding Ricci solitons (Huai-Dong Cao and Junming Xie, 2026)1Cao 2026 O(3)-symmetry of four-dimensional steady Ricci solitons (Hanbing Fang, 2026)4Fang 2026
Closer to the centre: more closely connected. Clockwise from the top: oldest to newest. Ricci flowWider flowsalso connected to each other
  1. A note on the classification of four-dimensional gradient steady and expanding Ricci solitons

    Huai-Dong Cao and Junming Xie PDF

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

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

    Huai-Dong Cao and Junming Xie PDF

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

  3. 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 “curvature estimates”, “four dimensional”

  4. -symmetry of four-dimensional steady Ricci solitons

    Hanbing Fang PDF

    Topics 4-manifolds, Ricci solitons · Shared terms “steady Ricci”, “dimensional gradient”, “four dimensional”

  5. Curvature pinching of asymptotically conical gradient expanding Ricci solitons

    Huai-Dong Cao and Junming Xie PDF

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

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

    Huai-Dong Cao and Junming Xie PDF

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

  7. Correction to: Curvature growth of some 4-dimensional gradient Ricci soliton singularity models

    Bennett Chow, Michael H. Freedman, Henry Shin et al. PDF

    Topics 4-manifolds, Ricci solitons · Shared terms “dimensional gradient”, “gradient Ricci”

  8. On Euler characteristic and Hitchin-Thorpe inequality for four-dimensional compact Ricci solitons

    Xu Cheng, Ernani Ribeiro and Detang Zhou PDF

    Topics 4-manifolds, Ricci solitons · Shared terms “four dimensional”, “gradient Ricci”, “addition”

Read around it

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

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

  2. 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.