Neil A. Watson – författare

This book is the first to be devoted entirely to the potential theory of the heat equation, and thus deals with time dependent potential theory. Its purpose is to give a logical, mathematically precise introduction to a subject where previously many proofs were not written in detail, due to their similarity with those of the potential theory of Laplace's equation. The approach to subtemperatures is a recent one, based on the Poisson integral representation of temperatures on a circular cylinder. Characterizations of subtemperatures in terms of heat balls and modified heat balls are proved, and thermal capacity is studied in detail. The generalized Dirichlet problem on arbitrary open sets is given a treatment that reflects its distinctive nature for an equation of parabolic type. Also included is some new material on caloric measure for arbitrary open sets. Each chapter concludes with bibliographical notes and open questions. The reader should have a good background in the calculus of functions of several variables, in the limiting processes and inequalities of analysis, in measure theory, and in general topology for Chapter 9.

This is first course in mathematical analysis, for students who have some familiarity with calculus, but are not familiar with formal proofs. All but the most straightforward proofs are worked out in detail before being presented formally in this book. Thus most of the ideas are expressed in two different ways; the first encourages and develops the intuition and the second gives a feeling for what constitutes a proof. In this way, intuition and rigor appear as partners rather than competitors. The informal discussions, the examples and the exercises may assume some familiarity with calculus, but the definitions, theorems and formal proofs are presented in the correct logical order and assume no prior knowledge of calculus. Thus some basic principles of calculus are blended into the presentation rather than being completely excluded.