Isoperimetric inequality and OMT: Difference between revisions

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A very interesting application of optimal transport is a proof of the isoperimetric inequality. The first proof with an OMT argument is due to Gromov and the main tool is the Knothe's map. <ref>V.D. Milman, G. Schechtman, Asymptotic Theory of Finite-Dimensional Normed Spaces, with an appendix by M. Gromov, Lecture notes in Mathematics, vol. 1200 (Springer, Berlin, 1986)</ref>. This proof is based on an idea by Knothe <ref> Herbert Knothe. "Contributions to the theory of convex bodies.." Michigan Math. J. 4 (1) 39 - 52, 1957 <ref>
 
==The classic isoperimetric inequality== 
A very interesting application of optimal transport is a proof of the isoperimetric inequality. The first proof with an OMT argument is due to Gromov and the main tool is the Knothe's map. <ref>V.D. Milman, G. Schechtman, Asymptotic Theory of Finite-Dimensional Normed Spaces, with an appendix by M. Gromov, Lecture notes in Mathematics, vol. 1200 (Springer, Berlin, 1986)</ref>. This proof is based on an idea by Knothe <ref>Herbert Knothe. "Contributions to the theory of convex bodies.." Michigan Math. J. 4 (1) 39 - 52, 1957</ref>. The classic isoperimetric inequality in <math> \mathbb{R}^n </math> states that the round ball has the minimal (n-1)-dimensional volume of the boundary among all the domains with a given fixed volume. This is equivalent to say that every set <math> E </math> has a larger perimeter than the ball <math> B </math> with the same volume. I will present this proof following the exposition given in chapter two in <ref> F. Santambrogio. Optimal Transport for Applied Mathematicians. Calculus of Variations, PDEs and Modeling (2015) </ref>. The usually way to state this is the following:
 
:<math> Per(E) \geq d \omega_d^{1/d}|E|^{1-1/d}. </math>

Revision as of 23:40, 11 February 2022

The classic isoperimetric inequality

A very interesting application of optimal transport is a proof of the isoperimetric inequality. The first proof with an OMT argument is due to Gromov and the main tool is the Knothe's map. [1]. This proof is based on an idea by Knothe [2]. The classic isoperimetric inequality in states that the round ball has the minimal (n-1)-dimensional volume of the boundary among all the domains with a given fixed volume. This is equivalent to say that every set has a larger perimeter than the ball with the same volume. I will present this proof following the exposition given in chapter two in [3]. The usually way to state this is the following:

  1. V.D. Milman, G. Schechtman, Asymptotic Theory of Finite-Dimensional Normed Spaces, with an appendix by M. Gromov, Lecture notes in Mathematics, vol. 1200 (Springer, Berlin, 1986)
  2. Herbert Knothe. "Contributions to the theory of convex bodies.." Michigan Math. J. 4 (1) 39 - 52, 1957
  3. F. Santambrogio. Optimal Transport for Applied Mathematicians. Calculus of Variations, PDEs and Modeling (2015)