1st Edition

Intuitive Axiomatic Set Theory

By José L Garciá Copyright 2024
362 Pages
by Chapman & Hall

362 Pages
by Chapman & Hall

Set theory can be rigorously and profitably studied through an intuitive approach, thus independently of formal logic. Nearly every branch of Mathematics depends upon set theory, and thus, knowledge of set theory is of interest to every mathematician. This book is addressed to all mathematicians and tries to convince them that this intuitive approach to axiomatic set theory is not only possible... Read more

I. The Zermelo-Fraenkel Theory

1.        Introduction

         1.1 The beginnings of set theory

         1.2 The antinomies

         1.3 Axiomatic theories

           1.4 Intuitive and formal axiomatic theories

           1.5 Axiomatic set theory

           1.6 Logical symbolism and truth tables

           1.7 Permutations

 

2.         Objects, Collections, Sets

          2.1 Introduction

           2.2 Membership and inclusion

           2.3 Intersections and unions

           2.4 Differences

           2.5 The first axioms

           2.6 Some remarks on the natural numbers

           2.7 Cartesian products

           2.8 Exercises

 

 

3.           Classes

          3.1 The formation of classes

                  3.1.1 Class sequences

                  3.1.2 Obtaining new classes

          3.2 Classes and formulas

                  3.2.1 Formulas describe classes

                  3.2.2 The tree of a formula

                  3.2.3 Other operations with classes

 

4.                   Relations

        4.1 Relations and operations with relations

         4.2 Order relations

                 4.2.1 Some types of relations

                 4.2.2 Order relations

                 4.2.3 Special elements in ordered classes

          4.3 Functional relations

                 4.3.1 Definitions and notations

                 4.3.2 Inversion and composition of functionals

         4.4 Partitions and equivalence relations

         4.5 Exercises

 

5.                   Maps, Orderings, Equivalences

        5.1 Central axioms and separation

             5.1.1 The axioms

              5.1.2 The principle of separation

              5.1.3 Some consequences of the axioms

       5.2 Maps

              5.2.1 Functions and maps

              5.2.2 Injective and surjective maps

              5.2.3 Relations, partitions, operations

       5.3 Exercises

 

6.                   Numbers and Infinity

            6.1 The axiom of infinity

                    6.1.1 Dedekind-Peano sets

                    6.1.2 Inductive sets

            6.2 A digression on the axiom of infinity

                    6.2.1 The set ω and natural numbers

                  6.2.2 Axiom 6 and property NNS

            6.3 The principle of induction

                   6.3.1 Natural induction

                   6.3.2 Well-orderings

                   6.3.3 Other forms of induction

           6.4 The recursion theorems

           6.5 The operations in  ω.

           6.6 Countable sets

           6.7 Integers and rationals

                 6.7.1 The ring Z of integers

                 6.7.2 The field of rational numbers

           6.8 The field of real numbers

           6.9 Exercises

 

 

                            7.          Pure Sets

     7.1 Transitivity

            7.1.1 Transitive closure of a set

            7.1.2 Pure sets

            7.1.3 Classes as universes

    7.2   ZF--universes

            7.2.1 The universe of pure sets

            7.2.2 The axiom of extension

    7.3   Relativization of classes

            7.3.1 Extensional apt classes

            7.3.2 Relativization

            7.3.3 C-absolute classes

    7.4 Exercises

 

8.                   Ordinals

     8.1 Well ordered classes and sets

     8.2 Morphisms between ordered sets

     8.3 Ordinals

     8.4 Induction and recursion

     8.5 Ordinal arithmetic

           8.5.1 Ordinal addition

           8.5.2 Ordinal multiplicatio

     8.6 Exercises

 

9.                   ZF-Universes

    9.1 Well founded sets

    9.2 The von Neumann universe of a universe

           9.2.1 The construction of V.

           9.2.2 V and the axioms

           9.2.3 The axiom of regularity

           9.2.4 Absoluteness in ZF.universes

   9.3 Well founded relations

           9.3.1 Induction and recursion for well founded relations

           9.3.2 Mostowski's theorem

   9.4 Exercises

 

10.               Cardinals and the Axiom of Choice

   10.1 Equipotent sets and cardinals

   10.2 Operations with cardinals

           10.2.1 Addition

           10.2.2 Multiplication

  10.3 The axiom of choice

           10.3.1 Choice and cardinals of sets

           10.3.2 Equivalent forms of the axiom of choice

  10.4 Finite and infinite sets

           10.4.1 Finiteness criteria

           10.4.2 The series of the alephs

  10.5 Cardinal exponentiation

           10.5.1 Exponentiation and the continuum hypothesis

           10.5.2 Infinite sums and products

  10.6 Cofinalities

           10.6.1 The cofinality of an ordinal

           10.6.2 More on cardinal arithmetic

  10.7 Exercises

II. Independence Results

 11.        Countable Universes

     11.1 The metatheory of sets

     11.2 Extensions and reliability

     11.3 ZF(C)*-universes

     11.4 Reflection theorems

     11.5 Inaccessible cardinals

     11.6 Exercises

 

12.               The constructible universe

      12.1 X-conxtructible sets

      12.2 The constructible hierarchy

      12.3 The constructible universe

      12.4 Constructibility implies choice

      12.5 The continuum hypothesis

              12.5.1 Overview

              12.5.2 Mostowski's isomorphism and constructibility

              12.5.3 Mostowski's isomorphism and ordinals

              12.5.4 The theorem

      12.6 Exercises

 

13.               Boolean Algebras

      13.1 Lattices

              13.1.1 Basic properties

              13.1.2 Filters, ideals and duality

              13.1.3 Distributive and complemented lattices

      13.2 Boolean algebras

      13.3 Complete lattices and algebras

               13.3.1 Complete Boolean algebras

               13.3.2 Separative orderings and complete algebras

               13.3.3 The completion of an ordered set

      13.4 Generic filters

      13.5 Exercises

 

14.           Generic extensions of a universe

      14.1 The basics

               14.1.1 Boolean universes

               14.1.2 The construction of a generic extension

     14.2 The generic universe is a ZFC-universe

               14.2.1 First axioms

               14.2.2 The axiom of the power set

               14.2.3 Elements and classes of a generic extension

               14.2.4 The axiom of replacement for generic extensions

               14.2.5 Infinity and choice

     14.3  Cardinals of generic extensions

     14.4  Exercises

 

15.          Independence proofs

     15.1 Pointed universes

     15.2 Cohen's theorem on the CH

               15.2.1 Overview

               15.2.2 A counterexample to CH

     15.3 Intermediate generic extensions

               15.3.1 Motivation

               15.3.2 Automorphisms of the algebra A

    15.4 The construction of the extension

               15.4.1 Another Boolean universe

               15.4.2 The universe M(G,₣)

    15.5 Cohen's theorem on the axiom of choice

               15.5.1 Overview

               15.5.2 The basic data

               15.5.3 The construction of the set Z

               15.5.4 A counterexample to AC

    15.6 Exercises

 

 

III. Appendices

 

 A.        The NBG-Theory

       A.1 Introduction

       A.2 NBG-universes

      A.3 NBG vs ZF

 

B.         Logic and Set Theory

       B.1 Introduction

       B.2 First-order set theory

              B.2.1 Language of set theory

              B.2.2 Deduction

      B.3 FOST and IST

              B.3.1 Evaluation of formulas

              B.3.2 Models of theories

     B.4 The completeness theorem and consequences

             B.4.1 The theorem

             B.4.2 Final remarks

 C.       Real Numbers Revisited

     C.1 Only one set of real numbers?

     

          

 

 

 

 

Biography

José Luis García is Emeritus Professor at the University of Murcia, Spain. He began his study of Mathematics at the University of Granada (Spain). After several years teaching Mathematics in secondary school, he was enrolled by the University of Murcia (Spain) as a member of the group working on algebra, led by Professor Gomez Pardo. He received his doctorate and a permanent position at the same university. He developed his research on Ring and Module Theory. He became full professor in 1991, and then served for thirty years.