2013/08/06 by Thomas Richard, Harish Seshadri, Richard, Thomas +1
Mathematics · Physics and Astronomy · #Advanced Differential Geometry Research #Differential Geometry (math.DG) #FOS: Mathematics #Geometric Analysis and Curvature Flows #Geometry and complex manifolds
paper · doi:10.48550/arxiv.1308.1190
openalex publication_date 2013/08/06 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
This note is a study of nonnegativity conditions on curvature which are preserved by the Ricci flow. We focus on specific kinds of curvature conditions which we call noncoercive, these are the conditions for which nonnegative curvature and vanishing scalar curvature doesn't imply flatness. We show that, in dimensions greater than 4, if a Ricci flow invariant condition is weaker than "Einstein with nonnegative scalar curvature", then this condition has to be "nonnegative scalar curvature". As a corollary, we obtain that a Ricci flow invariant curvature condition which is stronger than "nonnegative scalar curvature" cannot be (strictly) satisfied by compact Einstein symmetric spaces such as S2xS2 or CP2. We also investigate conditions which are satisfied by all conformally flat manifolds with nonnegative scalar curvature.