This book gives an up-to-date account of progress on Pansu's celebrated problem on the sub-Riemannian isoperimetric profile of the Heisenberg group. It also serves as an introduction to the general field of sub-Riemannian geometric analysis. It develops the methods and tools of sub-Riemannian differential geometry, nonsmooth analysis, and geometric measure theory suitable for attacks on Pansu's problem.

This volume presents research and expository articles by the participants of the 25th Arkansas Spring Lecture Series on Recent Progress in the Study of Harmonic Measure from a Geometric and Analytic Point of View held at the University of Arkansas, USA. Papers in this volume provide presentations of the problems that are at the forefront of harmonic analysis and partial differential equations. The following topics are featured: the solution of the Kato conjecture, the two bricks problem, new results on Cauchy integrals on non-smooth curves, the Neumann problem for sub-Laplacians, and a...

Recent developments in geometric measure theory and harmonic analysis have led to new and deep results concerning the regularity of the support of measures which behave asymptotically (for balls of small radius) as the Euclidean volume. A striking feature of these results is that they actually characterize flatness of the support in terms of the asymptotic behavior of the measure. Such characterizations have led to important new progress in the study of harmonic measure for non-smooth domains. This volume provides an up-to-date overview and an introduction to the research literature in this...