Reseña del libro "Real Variables: An Introduction To The Theory of Functions (en Inglés)"
This wonderful textbook, written by one of the preeminent teachers and researchers of analysis of the mid-20th century, gives a deep and comprehensive presentation of undergraduate real analysis of one and several variables that is accessible to any student with a good working knowledge of calculus and some experience with proofs, such as can be provided by a non-applied first linear algebra course or discrete mathematics course. The book lies midway in difficulty between the very basic analysis texts i.e. "baby real variables" texts that present a first course in rigorous single variable calculus and hard-edged real variables courses set in abstract metric spaces like Rudin and Pugh. It is also very broad in coverage. The republication of this book for the first time in nearly 50 years will provide an excellent choice for either a course text or self-study in undergraduate analysis.Several aspects of the book's unusual organization and content make it very deserving of low cost republication. Firstly, while it covers just about all the usual topics in any undergraduate analysis text-number systems, functions, limits of functions and sequences of one and several variables in ℝn, continuity, differentiation and integration of functions in ℝ, bounded sequences, metric spaces, basic point set topology, infinite series, power series, convergence tests, improper integrals, partial and total derivatives and multiple integrals- it has a number of unique aspects to the presentation that distinguish it from other textbooks. For example, a number of important concepts of analysis are covered in the starred sections and exercises that are not usually covered in these courses, such as point set topology, Riemann-Steijles integration, vector analysis and differential forms. Another excellent innovation that an entire opening chapter giving a far more detailed axiomatic description of the number systems without explicitly constructing them. While most analysis texts have such an opening section, Olmstead's is longer and more detailed then the ones found in most books with many substantial exercises. Another positive quality of the book is its' unusual midway level of difficulty. Calculus courses today are far weaker than they were when the standard textbooks such as Walter Rudin's Principles of Mathematical Analysis were published. As a result, a number of students beginning analysis today need a bit more foundational training in rigorous calculus before tackling functions in Euclidean spaces and abstract metric spaces. So usually students have to begin with a "baby real variables" text before moving on to analysis on metric spaces. Olmsted does a fine job in his early chapters of presenting the properties of the real numbers and a precise presentation of calculus on the real line. This allows the first half of the text to act as a "baby real variables" book i.e. a bridge between today's calculus courses and hard-edged classical analysis courses on metric spaces. As a result, students will only need one inexpensive text rather than two. Lastly, Olmsted contains "pragmatic" sections that discuss classical, more computational aspects of analysis that would be of great interest to applied mathematics, physics and engineering students. It's clear that Olmsted's book is an extraordinarily versatile textbook for undergraduate analysis courses at all levels. It will make a strong addition to the undergraduate analysis textbook literature and will be immensely useful to students and teachers alike as either a low-priced main textbook or as a supplement.
