Ulrich Dierkes Libros

This volume is the first in a three-part treatise on minimal surfaces, focusing on boundary value problems. It serves as a revised and expanded version of earlier monographs. The book opens with fundamental concepts of surface theory in three-dimensional Euclidean space, introducing minimal surfaces as stationary points of area or surfaces with zero mean curvature. A minimal surface is defined as a nonconstant harmonic mapping that is conformally parametrized and may have branch points. The classical theory of minimal surfaces is explored, featuring numerous examples, Björling’s initial value problem, reflection principles, and important theorems by Bernstein, Heinz, Osserman, and Fujimoto. The second part addresses Plateau’s problem and its modifications, presenting a new elementary proof that the area and Dirichlet integral share the same infimum for admissible surfaces spanning a prescribed contour. This leads to a simplified solution for minimizing both area and Dirichlet integral, along with new proofs of Riemann and Korn-Lichtenstein's mapping theorems, and a solution to the simultaneous Douglas problem for contours with multiple components. The volume also covers stable minimal surfaces, deriving curvature estimates and presenting uniqueness and finiteness results. Additionally, it develops a theory of unstable solutions to Plateau’s problems based on Courant’s mountain pass lemma and solves Dirichlet’s problem for non

Focusing on minimal surfaces with free boundaries, the book explores their boundary behavior and presents key results, including asymptotic expansions and Gauss-Bonnet formulas. It tackles the challenges of deriving regularity proofs for non-minimizers through indirect reasoning and monotonicity formulas. Geometric properties, enclosure theorems, and isoperimetric inequalities are examined, alongside discussions of obstacle problems and Plateau’s problem in Riemannian manifolds. The final chapter introduces a novel approach to the absence of interior branch points in area-minimizing solutions.

The exploration of minimal surfaces is deepened through a focus on existence, regularity, and uniqueness theorems for surfaces with partially free boundaries, highlighting the concept of "edge-crawling." A priori estimates for higher-dimensional minimal surfaces and singular integral minimizers are also discussed, leading to significant Bernstein theorems. Additionally, the book presents a comprehensive global theory, addressing the Douglas problem with Teichmüller theory, deriving index theorems, and introducing a topological perspective through Fredholm vector fields, all reflecting Smale's vision.