Gaussian isoperimetric inequality

In mathematics, the Gaussian isoperimetric inequality, proved by Boris Tsirelson and Vladimir Sudakov,[1] and later independently by Christer Borell,[2] states that among all sets of given Gaussian measure in the n-dimensional Euclidean space, half-spaces have the minimal Gaussian boundary measure.

Mathematical formulation

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Let be a measurable subset of endowed with the standard Gaussian measure with the density . Denote by

the ε-extension of A. Then the Gaussian isoperimetric inequality states that

where

Proofs and generalizations

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The original proofs by Sudakov, Tsirelson and Borell were based on Paul Lévy's spherical isoperimetric inequality.

Sergey Bobkov proved Bobkov's inequality, a functional generalization of the Gaussian isoperimetric inequality, proved from a certain "two point analytic inequality".[3] Bakry and Ledoux gave another proof of Bobkov's functional inequality based on the semigroup techniques which works in a much more abstract setting.[4] Later Barthe and Maurey gave yet another proof using the Brownian motion.[5]

The Gaussian isoperimetric inequality also follows from Ehrhard's inequality.[6][7]

See also

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References

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  1. ^ Sudakov, V. N.; Tsirel'son, B. S. (1978-01-01) [Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 41, pp. 14–24, 1974]. "Extremal properties of half-spaces for spherically invariant measures". Journal of Soviet Mathematics. 9 (1): 9–18. doi:10.1007/BF01086099. ISSN 1573-8795. S2CID 121935322.
  2. ^ Borell, Christer (1975). "The Brunn-Minkowski Inequality in Gauss Space". Inventiones Mathematicae. 30 (2): 207–216. Bibcode:1975InMat..30..207B. doi:10.1007/BF01425510. ISSN 0020-9910. S2CID 119453532.
  3. ^ Bobkov, S. G. (1997). "An isoperimetric inequality on the discrete cube, and an elementary proof of the isoperimetric inequality in Gauss space". The Annals of Probability. 25 (1): 206–214. doi:10.1214/aop/1024404285. ISSN 0091-1798.
  4. ^ Bakry, D.; Ledoux, M. (1996-02-01). "Lévy–Gromov's isoperimetric inequality for an infinite dimensional diffusion generator". Inventiones Mathematicae. 123 (2): 259–281. doi:10.1007/s002220050026. ISSN 1432-1297. S2CID 120433074.
  5. ^ Barthe, F.; Maurey, B. (2000-07-01). "Some remarks on isoperimetry of Gaussian type". Annales de l'Institut Henri Poincaré B. 36 (4): 419–434. Bibcode:2000AIHPB..36..419B. doi:10.1016/S0246-0203(00)00131-X. ISSN 0246-0203.
  6. ^ Latała, Rafał (1996). "A note on the Ehrhard inequality". Studia Mathematica. 2 (118): 169–174. doi:10.4064/sm-118-2-169-174. ISSN 0039-3223.
  7. ^ Borell, Christer (2003-11-15). "The Ehrhard inequality". Comptes Rendus Mathématique. 337 (10): 663–666. doi:10.1016/j.crma.2003.09.031. ISSN 1631-073X.