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The Globalization Theorem for the Curvature Dimension Condition

2016/12/22 by Fabio Cavalletti, Emanuel Milman, Cavalletti, Fabio +1 · 67 citations
Mathematics · Physics and Astronomy · #Advanced Differential Geometry Research #Bounded function #Curvature #Dimension (graph theory) #Geodesic #Geometric Analysis and Curvature Flows #Geometry #Geometry and complex manifolds #Mathematical analysis #Mathematics #Measure (data warehouse) #Order (exchange) #Pure mathematics #Ricci curvature #Space (punctuation) #math.FA #math.MG

paper · pdf · open access · doi:10.1007/s00222-021-01040-6

published in Inventiones mathematicae 226(1), 1-137 (Springer Science+Business Media) · 92 pages; polished the introduction, added some heuristic arguments to provide insight, and corrected typos. To appear in Inventiones Mathematicae

arxiv created 2021/02/24 · arxiv updated 2021/02/26 · openalex publication_date 2021/08/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04

Abstract

The Lott-Sturm-Villani Curvature-Dimension condition provides a synthetic notion for a metric-measure space to have Ricci-curvature bounded from below and dimension bounded from above. We prove that it is enough to verify this condition locally: an essentially non-branching metric-measure space (X,\mathsf d,\mathfrak m) (so that (supp \mathfrak m,\mathsf d) is a length-space and \mathfrak m(X) < ∞) verifying the local Curvature-Dimension condition CDloc(K,N) with parameters K ∈ ℝ and N ∈ (1,∞), also verifies the global Curvature-Dimension condition CD(K,N). In other words, the Curvature-Dimension condition enjoys the globalization (or local-to-global) property, answering a question which had remained open since the beginning of the theory. For the proof, we establish an equivalence between L1 and L2 optimal-transport-based interpolation. The challenge is not merely a technical one, and several new conceptual ingredients which are of independent interest are developed: an explicit change-of-variables formula for densities of Wasserstein geodesics depending on a second-order temporal derivative of associated Kantorovich potentials; a surprising third-order theory for the latter Kantorovich potentials, which holds in complete generality on any proper geodesic space; and a certain rigidity property of the change-of-variables formula, allowing us to bootstrap the a-priori available regularity. As a consequence, numerous variants of the Curvature-Dimension condition proposed by various authors throughout the years are shown to, in fact, all be equivalent in the above setting, thereby unifying the theory.

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