Christian Ketterer

Albert-Ludwigs-Universität Freiburg

Mathematisches Institut
Ernst-Zermelo-Str. 1
79104 Freiburg

Office: Ernst-Zermelo-Str. 1, Raum 337

Phone: +49 761 203 5563
Home Research Teaching



  1. GROMOV-HAUSDORFF STABILITY OF TORI UNDER RICCI AND INTEGRAL SCALAR CURVATURE BOUNDS (joint with Shouhei Honda, Ilaria Mondello, Raquel Perales, Chiara Rigoni), preprint [arxiv]


  1. Characterization of the null energy condition via displacement convexity of entropy, J. Lond. Math. Soc. [journal]
  2. Rigidity of mean convex subsets in non-negatively curved RCD spaces and stability of mean curvature bounds, J. Top. and Anal. [journal]
  3. The rigidity of sharp spectral gap in nonnegatively curved spaces (joint with Yu Kitabeppu and Sajjad Lakzian), Nonlin. Anal. 228(2023), Paper No. 113202, 62 pp. [journal]
  4. On the structure of RCD spaces with upper curvature bounds (joint with Vitali Kapovitch and Martin Kell), Math. Zeitschrift., 301, 3469-3502 (2022) [journal]
  5. Stability of metric measure spaces with integral Ricci curvature bounds, J. Funct. Anal. , vol 281, Issue 8, 2021, 109142 [journal]
  6. On gluing Alexandrov spaces with lower Ricci curvature bounds (joint with Vitali Kapovitch and Karl-Theodor Sturm), accepted in Comm. Anal. and Geom. [journal]
  7. Inscribed radius bounds for lower ricci bounded metric measure spaces with mean convex boundary (joint with Annegret Burtscher, Robert McCann and Eric Woolgar), SIGMA Symmetry Integrability Geom. Methods Appl. 16 (2020), Paper No. 131, 29 pp. [journal]
  8. Stability of graphical tori with almost nonnegative scalar curvature (joint with Armando J. Cabrera Pacheco and Raquel Perales), Calc. Var. Partial Differential Equations 59 (2020), no. 4, 134 [journal]
  9. The Heintze-Karcher inequality for metric measure spaces, Proc. Americ. Math. Soc. 148 (2020), no. 9, 4041-4056 [journal]
  10. Stratified spaces and synthetic Ricci curvature bounds (joint with Jerome Bertrand, Ilaria Mondello and Thomas Richard), Annales l'Institut Fourier, Volume 71 (2021) no. 1, pp. 123-173. [journal]
  11. Weakly noncollapsed RCD spaces with upper curvature bounds (joint with Vitali Kapovitch), Anal. Geom. Metr. Spaces 7 (2019), no. 1, 197-211 [journal]
  12. CD meets CAT (joint with Vitali Kapovitch), J. Reine Angew. Math., https://doi:10.1515/crelle-2019-0021. [journal]
  13. Rigidity for the spectral gap of $RCD(K,\infty)$-spaces (joint with Nicola Gigli, Kazumasa Kuwada, Shin-ichi Ohta), Amer. J. Math. 142 (2020), no. 5, 1559–1594 [journal]
  14. Lagrangian calculus for non-symmetric diffusion operators, Adv. Calc. Var. , [journal]
  15. Sectional and intermediate Ricci curvature lower bounds via Optimal Transport (joint with Andrea Mondino), Adv. Math. 329:781-818, 2018 [journal]
  16. On the geometry of metric measure spaces with variable curvature bounds, J. Geom. Anal. 27 (2017) no.3, 1951-1994 [journal]
  17. Obata's Rigidity Theorem for Metric Measure Spaces, Anal. Geom. Metr. Spaces 3, 278-295, 2015 [journal]
  18. Failure of topological splitting and topological maximal diameter theorems for $MCP$-spaces (joint with Tapio Rajala), Potential Anal. 42 (2015) , no.3, 645-655 [journal]
  19. Cones over metric measure spaces and the maximal diameter theorem, J. Math. Pures Appl. (9) 103 (2015), no. 5, 1228-1275 [journal]
  20. Ricci curvature bounds for warped products, J. Funct. Anal. 265(2): 266-299, 2013. [journal]


Other publications

  • Evolution variational inequality and Wasserstein control in variable curvature context, preprint [arxiv]