Isaac Goldbring - Böcker

Ultrafilters and ultraproducts provide a useful generalization of the ordinary limit processes which have applications to many areas of mathematics. Typically, this topic is presented to students in specialized courses such as logic, functional analysis, or geometric group theory. In this book, the basic facts about ultrafilters and ultraproducts are presented to readers with no prior knowledge of the subject and then these techniques are applied to a wide variety of topics. The first part of the book deals solely with ultrafilters and presents applications to voting theory, combinatorics, and topology, while also dealing also with foundational issues.The second part presents the classical ultraproduct construction and provides applications to algebra, number theory, and nonstandard analysis. The third part discusses a metric generalization of the ultraproduct construction and gives example applications to geometric group theory and functional analysis. The final section returns to more advanced topics of a more foundational nature.The book should be of interest to undergraduates, graduate students, and researchers from all areas of mathematics interested in learning how ultrafilters and ultraproducts can be applied to their specialty.

The goal of this monograph is to give an accessible introduction to nonstandard methods and their applications, with an emphasis on combinatorics and Ramsey theory. It includes both new nonstandard proofs of classical results and recent developments initially obtained in the nonstandard setting. This makes it the first combinatorics-focused account of nonstandard methods to be aimed at a general (graduate-level) mathematical audience. This book will provide a natural starting point for researchers interested in approaching the rapidly growing literature on combinatorial results obtained via nonstandard methods. The primary audience consists of graduate students and specialists in logic and combinatorics who wish to pursue research at the interface between these areas.

This monograph introduces the reader to the increasingly popular topic of computable metric structure theory, a subject which unifies methods from effective analysis and computable algebra into one coherent framework. Computable structure theory had been constrained to the algebraic and discrete realms, but in the past 10 years or so, much work has been done in extending this topic to structures from analysis such as metric spaces, Banach spaces, and operator algebras. This book is the first comprehensive treatment of these basic results and discusses several challenging open problems that have arisen.  The book provides a foundation for the study of classic objects from functional analysis using tools from continuous model theory and computable structure theory.  It is largely self contained, though it is assumed that the reader is familiar with first-order logic. It should prove useful to students and researchers in continuous logic looking to familiarize themselves with computable structure theory as well as to researchers in the latter field looking to extend their work to structures from analysis. The discussion contains a large number of well-crafted examples and could provide the basis for a course or seminar in this area.