Sobolev Spaces on Metric Measure Spaces An Approach Based on Upper Gradients [Hardcover]

This coherent treatment from first principles is an ideal introduction for graduate students and a useful reference for experts.Analysis on metric spaces is a field that has expanded dramatically since the 1990s. Written by some of the founders of the theory, this book provides a coherent treatment from first principles. It is an ideal introduction for graduate students and a useful reference for experts in the field.Analysis on metric spaces is a field that has expanded dramatically since the 1990s. Written by some of the founders of the theory, this book provides a coherent treatment from first principles. It is an ideal introduction for graduate students and a useful reference for experts in the field.Analysis on metric spaces emerged in the 1990s as an independent research field providing a unified treatment of first-order analysis in diverse and potentially nonsmooth settings. Based on the fundamental concept of upper gradient, the notion of a Sobolev function was formulated in the setting of metric measure spaces supporting a Poincar? inequality. This coherent treatment from first principles is an ideal introduction to the subject for graduate students and a useful reference for experts. It presents the foundations of the theory of such first-order Sobolev spaces, then explores geometric implications of the critical Poincar? inequality, and indicates numerous examples of spaces satisfying this axiom. A distinguishing feature of the book is its focus on vector-valued Sobolev spaces. The final chapters include proofs of several landmark theorems, including Cheeger's stability theorem for Poincar? inequalities under GromovHausdorff convergence, and the KeithZhong self-improvement theorem for Poincar? inequalities.Preface; 1. Introduction; 2. Review of basic functional analysis; 3. Lebesgue theory of Banach space-valued functions; 4. Lipschitz functions and embeddings; 5. Path integrals and modulus; 6. Upper gradients; 7. Sobolev spaces; 8. Poincar? inequalitieslÃ{