Sets for Mathematics (Book)

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The textbook Sets for Mathematics by F. William Lawvere uses categorical algebra to introduce set theory.

Basic Mathematics
Lawvere Sets for Mathematics Cover.jpg
Information
Author F. William Lawvere
Language English
Publisher Cambridge University Press
Publication Date 10 April 2003
Pages 276
ISBN-10 0521010608
ISBN-13 978-0521010603

In parallel to Grothendieck, Lawvere developed the notion of a topos as a collection of objects/points behaving as sets and arrows as maps between sets. The utility of this is for a characterization of sets via mappings only - there is a unique (equivalence class of) set(s) with one element that can alternatively be described as only receiving one map from each other set. The number of maps in the other direction count the elements of sets conversely. Two element sets are an instance of "subobject classifiers" in the topos of sets such that the maps into them correspond to subsets of the source set of the map. The language of toposes is particularly accessible here, and plays a universal role in modern mathematics, e.g. for toposes emerging from sets parametrized by a topological space (presheaf toposes) even inspiring functional programming languages such as Haskell due to the logical properties of toposes.

Table of Contents

Chapter/Section # Title Page #
Foreword ix
Contributors to Sets for Mathematics xiii
1. Abstract Sets and Mappings
1.1 Sets, Mappings, and Composition 1
1.2 Listings, Properties, and Elements 4
1.3 Surjective and Injective Mappings 8
1.4 Associativity and Categories 10
1.5 Separators and the Empty Set 11
1.6 Generalized Elements 15
1.7 Mappings as Properties 17
1.8 Additional Exercises 23
2. Sums, Monomorphisms, and Parts
2.1 Sum as a Universal Property 26
2.2 Monomorphisms and Parts 32
2.3 Inclusion and Membership 34
2.4 Characteristic Functions 38
2.5 Inverse Image of a Part 40
2.6 Additional Exercises 44
3. Finite Inverse Limits
3.1 Retractions 48
3.2 Isomorphism and Dedekind Finiteness 54
3.3 Cartesian Products and Graphs 58
3.4 Equalizers 66
3.5 Pullbacks 69
3.6 Inverse Limits 71
3.7 Additional Exercises 75
Colimits, Epimorphisms, and the Axiom of Choice
4.1 Colimits are Dual to Limits 78
4.2 Epimorphisms and Split Surjections 80
4.3 The Axiom of Choice 84
4.4 Partitions and Equivalence Relations 85
4.5 Split Images 89
4.6 The Axiom of Choice as the Distinguishing Property of Constant/Random Sets 92
4.7 Additional Exercises 94
5. Mapping Sets and Exponentials
5.1 Natural Bijection and Functoriality 96
5.2 Exponentiation 98
5.3 Functoriality of Function Spaces 102
5.4 Additional Exercises 108
6. Summary of the Axioms and an Example of Variable Sets
6.1 Axioms for Abstract Sets and Mappings 111
6.2 Truth Values for Two-Stage Variable Sets 114
6.3 Additional Exercises 117
7. Consequences and Uses of Exponentials
7.1 Concrete Duality: The Behavior of Monics and Epics under the Contravariant Functoriality of Exponentiation 120
7.2 The Distributive Law 126
7.3 Cantor's Diagonal Argument 129
7.4 Additional Exercises 134
8. More on Power Sets
8.1 Images 136
8.2 The Covariant Power Set Functor 141
8.3 The Natural Map \(Placeholder\) 145
8.4 Measuring, Averaging, and Winning with \(V\)-Valued Quantities 148
8.5 Additional Exercises 152
9. Introduction to Variable Sets
9.1 The Axiom of Infinity: Number Theory 154
9.2 Recursion 157
9.3 Arithmetic of \(N\) 160
9.4 Additional Exercises 165
10. Models of Additional Variation
10.1 Monoids, Podsets, and Groupoids 167
10.2 Actions 171
10.3 Reversible Graphs 176
10.4 Chaotic Graphs 180
10.5 Feedback and Control 186
10.6 To and from Idempotents 189
10.7 Additional Exercises 191
Appendixes
A. Logic as the Algebra of Parts
A.0 Why Study Logic? 193
A.1 Basic Operators and Their Rules of Inference 195
A.2 Fields, Nilpotents, Idempotents 212
B. Logic as the Algebra of Parts 220
C. Definitions, Symbols, and the Greek Alphabet
C.1 Definitions of Some Mathematical and Logical Concepts 231
C.2 Mathematical Notations and Logical Symbols 251
C.3 The Greek Alphabet 252
Bibliography 253
Index 257