Elementary Topology: A Course in Point Set Topology

This book is an introduction to point set topology for undergraduates. Many of the classic textbooks on the subject cover the subject exhaustively and at the highest possible level of generality. The result of using traditional textbooks has been that students spend 2 semesters learning far more general topology on abstract spaces then most of them will ever need to use or know. More importantly, students get the impression from geometers and topologists in later courses that they “wasted” a year of their studies learning material that most mathematicians don’t even consider topology anymore. This leaves many of them feeling deceived and frustrated. Unfortunately, the reaction has been in recent decades to write elementary topology textbooks that only present the barest minimum of point set topology needed for students in advanced geometry or algebraic topology. Indeed-some recent beginning textbooks in topology largely skip general topology altogether and jump straight into algebraic and geometric topology such as homotopy, curves and surfaces! We believe this ludicrous solution is essentially throwing the baby out with the bathwater. This reissued edition of Hall/ Spencer should seriously be considered by mathematicians as the benchmark for such a course. The book contains what we believe to be approximately the irreducible minimum of point set topology any student of mathematics needs to learn regardless of level or interest. The book is quite detailed, covering sufficient general topology of interest and use for analysts, geometers and topologists. The book falls into two rather distinct parts. The first half is concerned with an introductory study of topological and metric spaces. The basic operations with sets are introduced in Chapter I, relations and mappings are discussed, and an introduction to infinite and uncountable sets is given. Chapter 2 introduces the basic topological structure of the real numbers in a review of basic analysis. In Chapter 3, general topological and metric spaces are introduced and such topics as compactness, separation and continuous functions are discussed. Metric spaces are pursued further in Chapter 4, with discussions of local connectivity, countability, metrizability and completion being included. The second part is less elementary in character. The long Chapter 5 is concerned with giving topological characterizations of arcs, simple closed curves, and simple closed surfaces. Peano spaces are discussed and the Jordan curve theorem and Jordan-Schoenflies theorem are proved. Chapter 6 discusses partitionable spaces, a topic often missing from modern texts. Finally, Chapter 7 discusses the axiom of choice, Zorn's lemma (in the form commonly called the Hausdorff niaximality principle) and the Tychonoff product theorem. The book in particular will help students understand the deep connection between general topology and real and complex analysis. The most natural path towards understanding abstract topological spaces, general continuous mappings and topological invariants on families of open sets is to see how they directly generalize the usual structures of analysis on the real line. Also. Blue Collar Scholar founder/editor Karo Maestro has added his usual personal touch to the new edition, with a new preface on his own reflections on point set topology and recommendations for supplementary or subsequent study. The prerequisites for the text are very minimal-just calculus and some experience with rigorous proofs. This wonderful lost text in this new inexpensive edition will serve a new generation of mathematics students who need to learn this crucial foundational subject with a presentation that’s both detailed and informative without being exhaustive. It will indoctrinate students into the beauty and simplicity of point-set topology and convince them of its’ intrinsic importance-primarily to analysis, but also to other areas of mathematics.