The Brunn--Minkowski Inequality and Nontrivial Cycles in the Discrete Torus

نویسندگان

  • Noga Alon
  • Ohad N. Feldheim
چکیده

Let (Cd m)∞ denote the graph whose set of vertices is Zd m in which two distinct vertices are adjacent iff in each coordinate either they are equal or they differ, modulo m, by at most 1. Bollobás, Kindler, Leader, and O’Donnell proved that the minimum possible cardinality of a set of vertices of (Cd m)∞ whose deletion destroys all topologically nontrivial cycles is md − (m− 1)d. We present a short proof of this result, using the Brunn–Minkowski inequality, and also show that the bound can be achieved only by selecting a value xi in each coordinate i, 1 ≤ i ≤ d, and by keeping only the vertices whose ith coordinate is not xi for all i.

برای دانلود رایگان متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Volume difference inequalities for the projection and intersection bodies

In this paper, we introduce a new concept of volumes difference function of the projection and intersection bodies. Following this, we establish the Minkowski and Brunn-Minkowski inequalities for volumes difference function of the projection and intersection bodies.

متن کامل

A Curved Brunn-Minkowski Inequality on the Discrete Hypercube, Or: What Is the Ricci Curvature of the Discrete Hypercube?

We compare two approaches to Ricci curvature on nonsmooth spaces in the case of the discrete hypercube {0, 1}N . While the coarse Ricci curvature of the first author readily yields a positive value for curvature, the displacement convexity property of Lott, Sturm, and Villani could not be fully implemented. Yet along the way we get new results of a combinatorial and probabilistic nature, includ...

متن کامل

A Curved Brunn–minkowski Inequality on the Discrete Hypercube Or: What Is the Ricci Curvature of the Discrete Hypercube? Y. Ollivier and C. Villani

We compare two approaches to Ricci curvature on non-smooth spaces, in the case of the discrete hypercube {0, 1} . While the coarse Ricci curvature of the first author readily yields a positive value for curvature, the displacement convexity property of Lott, Sturm and the second author could not be fully implemented. Yet along the way we get new results of a combinatorial and probabilistic natu...

متن کامل

A Brunn-minkowski Inequality for the Integer Lattice

A close discrete analog of the classical Brunn-Minkowksi inequality that holds for finite subsets of the integer lattice is obtained. This is applied to obtain strong new lower bounds for the cardinality of the sum of two finite sets, one of which has full dimension, and, in fact, a method for computing the exact lower bound in this situation, given the dimension of the lattice and the cardinal...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

عنوان ژورنال:
  • SIAM J. Discrete Math.

دوره 24  شماره 

صفحات  -

تاریخ انتشار 2010