Translations of Mathematical Monographs 2002; 256 pp; hardcover Volume: 214 ISBN10: 0821827650 ISBN13: 9780821827659 List Price: US$109 Member Price: US$87.20 Order Code: MMONO/214
 An algebra \(A\) on a set \(X\) is a family of subsets of this set closed under the operations of union and difference of two subsets. The main topic of the book is the study of various algebras and families of algebras on an abstract set \(X\). The author shows how this is related to famous problems by Lebesgue, Banach, and Ulam on the existence of certain measures on abstract sets, with corresponding algebras being algebras of measurable subsets with respect to these measures. In particular it is shown that for a certain algebra not to coincide with the algebra of all subsets of \(X\) is equivalent to the existence of a nonmeasurable set with respect to a given measure. Although these questions don't seem to be related to mathematical logic, many results in this area were proved by "metamathematical" methods, using the method of forcing and other tools related to axiomatic set theory. However, in the present book, the author uses "elementary" (mainly combinatorial) methods to study properties of algebras on a set. Presenting new and original material, the book is written in a clear and readable style and illustrated by many examples and figures. The book will be useful to researchers and graduate students working in set theory, mathematical logic, and combinatorics. Readership Graduate students and research mathematicians interested in foundations of mathematics and logic. Table of Contents  Introduction
 Main results
 The main idea
 Finite sequences of algebras (1). Proof of Theorems 2.1 and 2.2
 Countable sequences of algebras (1). Proof of Theorem 2.4
 Proof of the GitikShelah theorem, and more from set theory
 Proof of Theorems 1.17, 2.7, 2.8
 Theorems on almost \(\sigma\)algebras. Proof of Theorem 2.9
 Finite sequences of algebras (2). The function \(\mathfrak{g}(n)\)
 A description of the class of functions \(\Psi_*^7\)
 The general problem. Proof of Theorems 2.15 and 2.20
 Proof of Theorems 2.21(1,3), 2.24
 The inverse problem
 Finite sequences of algebras (3). Proof of Theorems 2.27, 2.31, 2.36, 2.38
 Preliminary notions and lemmas
 Finite sequences of algebras (4). Proof of Theorems 2.39(1,2), 2.45(1,2)
 Countable sequences of algebras (2). Proof of Theorems 2.29, 2.32, 2.46
 A refinement of theorems on \(\sigma\)algebras. Proof of Theorems 2.34, 2.44
 Semistructures and structures of sets. Proof of Theorem 2.48
 Final comments. Generalization of Theorem 2.1
 Appendix: On a question of Grinblat by S. Shelah
 Bibliography
 Index
