A General Method to Determine Limiting Optimal Shapes for Edge-Isoperimetric Inequalities

Ellen Veomett, Emmanuel Tsukerman

Research output: Contribution to journalArticlepeer-review

Abstract

For a general family of graphs on Zn, we translate the edge-isoperimetric problem into a continuous isoperimetric problem in Rn. We then solve the continuous isoperimetric problem using the Brunn-Minkowski inequality and Minkowski's theorem on Mixed Volumes. This translation allows us to conclude, under a reasonable assumption about the discrete problem, that the shapes of the optimal sets in the discrete problem approach the shape of the optimal set in the continuous problem as the size of the set grows. The solution is the zonotope defined as the Minkowski sum of the edges of the original graph.
We demonstrate the efficacy of this method by revisiting some previously solved classical edge-isoperimetric problems. We then apply our method to some discrete isoperimetric problems which had not previously been solved. The complexity of those solutions suggest that it would be quite difficult to find them using discrete methods only.

Original languageAmerican English
JournalThe Electronic Journal of Combinatorics
Volume24
StatePublished - Feb 17 2017

Keywords

  • Discrete isoperimetric problem
  • Continuous isoperimetric problem
  • Infinite graphs
  • Lattices

Disciplines

  • Computer Sciences
  • Mathematics

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