Abstract
We give a new proof of the Caffarelli contraction theorem, which states that the Brenier optimal transport map sending the standard Gaussian measure onto a uniformly log-concave probability measure is Lipschitz. The proof combines a recent variational characterization of Lipschitz transport map by the second author and Juillet with a convexity property of optimizers in the dual formulation of the entropy-regularized optimal transport (or Schrödinger) problem.
Similar content being viewed by others
References
Ambrosio, L., Gigli, N., Savaré, G.: Gradient Flows in Metric Spaces and in the Space of Probability Measures. Lectures in Mathematics, 2nd edn. ETH Zürich, Birkhäuser Verlag, Basel (2008)
Benamou, J.-D., Carlier, G., Cuturi, M., Nenna, L., Peyré, G.: Iterative Bregman projections for regularized transportation problems. SIAM J. Sci. Comput. 37(2), A1111–A1138 (2015)
Caffarelli, L.A.: Monotonicity properties of optimal transportation and the FKG and related inequalities. Commun. Math. Phys. 214(3), 547–563 (2000)
Caffarelli, L.A.: Erratum: “Monotonicity of optimal transportation and the FKG and related inequalities” [Commun. Math. Phys. 214(3), 547–563 (2000)]. Commun. Math. Phys. 225(2), 449–450 (2002)
Carlier, G., Duval, V., Peyré, G., Schmitzer, B.: Convergence of entropic schemes for optimal transport and gradient flows. SIAM J. Math. Anal. 49(2), 1385–1418 (2017)
Chen, Y., Georgiou, T., Pavon, M.: Entropic and displacement interpolation: a computational approach using the Hilbert metric. SIAM J. Math. Anal. 76(6), 2375–2396 (2016)
Colombo, M., Figalli, A., Jhaveri, Y.: Lipschitz changes of variables between perturbations of log-concave measures. Ann. Sc. Norm. Super. Pisa Cl. Sci. (5) 17(4), 1491–1519 (2017)
Conforti, G.: A second order equation for Schrödinger bridges with applications to the hot gas experiment and entropic transportation cost. Probab. Theory Relat. Fields 174(1–2), 1–47 (2019)
Conforti, G., Ripani, L.: Around the entropic Talagrand inequality. arXiv preprint arXiv:1809.02062 (2018)
Cordero-Erausquin, D.: Some applications of mass transport to Gaussian-type inequalities. Arch. Ration. Mech. Anal. 161(3), 257–269 (2002)
Courtade, T.A., Fathi, M., Pananjady, A.: Quantitative stability of the entropy power inequality. IEEE Trans. Inf. Theory 64(8), 5691–5703 (2018)
Csiszár, I.: \(I\)-divergence geometry of probability distributions and minimization problems. Ann. Probab. 3, 146–158 (1975)
Cuturi, M.: Sinkhorn distances: lightspeed computation of optimal transport. Adv. Neural Inf. Process. Syst. (NIPS) 2013(26), 2292–2300 (2013)
De Philippis, G., Figalli, A.: Rigidity and stability of Caffarelli’s log-concave perturbation theorem. Nonlinear Anal. 154, 59–70 (2017)
Essid, M., Pavon, M.: Traversing the Schrödinger bridge strait: Robert Fortet’s marvelous proof redux. J. Optim. Theory Appl. 181(1), 23–60 (2019)
Fortet, R.: Résolution d’un système d’équations de M. Schrödinger. J. Math. Pures Appl. 19, 83–105 (1940)
Franklin, J., Lorenz, J.: On the scaling of multidimensional matrices. Linear Algebra Appl. 114(115), 717–735 (1989)
Genevay, A.: Entropy-regularized optimal transport for machine learning. Ph.D. Thesis, Université Paris-Dauphine, (2019)
Gentil, I., Léonard, C., Ripani, L.: About the analogy between optimal transport and minimal entropy. Ann. Fac. Sci. Toulouse Math. (6) 26(3), 569–601 (2017)
Gentil, I., Léonard, C., Ripani, L., Tamanini, L.: An entropic interpolation proof of the HWI inequality. Stoch. Process. Appl. 130, 907–923 (2019)
Gigli, N., Tamanini, L.: Benamou–Brenier and duality formulas for the entropic cost on \({RCD}^*(k,n)\) spaces. arxiv preprint (2018)
Gozlan, N., Madiman, M., Roberto, C., Samson, P.M.: Deviation inequalities for convex functions motivated by the Talagrand conjecture. Zap. Nauchn. Sem. S.-Peterburg. Otdel. Mat. Inst. Steklov. (POMI) 457 (2017), no. Veroyatnost’ i Statistika. 25, 168–182 (2017)
Gozlan, N., Juillet, N.: On a mixture of Brenier and Strassen theorems. Proc. Lond. Math. Soc. (3) 120(3), 434–463 (2020)
Guionnet, A., Shlyakhtenko, D.: Free monotone transport. Invent. Math. 197(3), 613–661 (2014)
Hargé, G.: A particular case of correlation inequality for the Gaussian measure. Ann. Probab. 27(4), 1939–1951 (1999)
Hargé, G.: Inequalities for the Gaussian measure and an application to Wiener space. C. R. Acad. Sci. Paris Sér. I Math. 333(8), 791–794 (2001)
Hiriart-Urruty, J.-B., Lemaréchal, C.: Fundamentals of Convex Analysis. Grundlehren Text Editions. Springer, Berlin (2001)
Hiriart-Urruty, J.-B., Lemaréchal, C.: Convex Analysis and Minimization Algorithms. I, Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 305, Springer, Berlin (1993)
Kim, Y.-H., Milman, E.: A generalization of Caffarelli’s contraction theorem via (reverse) heat flow. Math. Ann. 354(3), 827–862 (2012)
Klartag, B.: Poincaré inequalities and moment maps. Ann. Fac. Sci. Toulouse Math. 22(1), 1–41 (2013)
Kolesnikov, A.V.: Global Hölder estimates for optimal transportation. Mat. Zametki 88(5), 708–728 (2010)
Kolesnikov, A.V.: On Sobolev regularity of mass transport and transportation inequalities. Theory Probab. Appl. 57(2), 243–264 (2013)
Léonard, C.: From the Schrödinger problem to the Monge–Kantorovich problem. J. Funct. Anal. 262(4), 1879–1920 (2012)
Léonard, C.: A survey of the Schrödinger problem and some of its connections with optimal transport. Discrete Contin. Dyn. Syst. 34(4), 1533–1574 (2014)
Léonard, C.: Revisiting Fortet’s proof of existence of a solution to the Schrödinger system. ArXiv preprint arXiv:1904.13211 (2019)
Mikami, T.: Monge’s problem with a quadratic cost by the zero-noise limit of \(h\)-path processes. Probab. Theory Relat. Fields 129(2), 245–260 (2004)
Milman, E.: On the role of convexity in isoperimetry, spectral gap and concentration. Invent. Math. 177(1), 1–43 (2009)
Milman, E.: Spectral estimates, contractions and hypercontractivity. J. Spectr. Theory 8(2), 669–714 (2018)
Prékopa, A.: On logarithmic concave measures and functions. Acta Sci. Math. (Szeged) 34, 335–343 (1973)
Rockafellar, R.T.: Convex Analysis. Princeton Mathematical Series, No. 28. Princeton University Press, Princeton (1970)
Schrödinger, E.: Sur la théorie relativiste de l’électron et l’interprétation de la mécanique quantique. Ann. Inst. H. Poincaré 2(4), 269–310 (1932)
Villani, C.: Topics in Optimal Transportation. Graduate Studies in Mathematics, vol. 58. American Mathematical Society, Providence (2003)
Villani, C.: Optimal Transport. Grundlehren der Mathematischen Wissenschaften [Fundamental Principles of Mathematical Sciences], vol. 338. Springer, Berlin (2009)
Acknowledgements
MF and NG were supported by ANR-11-LABX-0040-CIMI within the program ANR-11-IDEX- 0002-02. MF and MP were supported by Projects MESA (ANR-18-CE40-006) and EFI (ANR-17-CE40-0030) of the French National Research Agency (ANR). NG is supported by a grant of the Simone and Cino Del Duca Foundation. We thank Christian Léonard for pointing out to us Fortet’s work and sharing a preliminary version of [35] explaining it, Gabriel Peyré for his lectures on numerical optimal transport in March 2019 in Toulouse, and Franck Barthe, Nicolas Juillet and Michel Ledoux for useful discussions. We also thank an anonymous referee for his valuable comments, and for a suggestion that simplified the proof of Theorem 15.
Author information
Authors and Affiliations
Corresponding author
Additional information
Communicated by X. Cabre.
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Rights and permissions
About this article
Cite this article
Fathi, M., Gozlan, N. & Prod’homme, M. A proof of the Caffarelli contraction theorem via entropic regularization. Calc. Var. 59, 96 (2020). https://doi.org/10.1007/s00526-020-01754-0
Received:
Accepted:
Published:
DOI: https://doi.org/10.1007/s00526-020-01754-0