Natural Dualities for the Working Algebraist

Couverture
Cambridge University Press, 12 nov. 1998 - 356 pages
The theory of natural dualities, as presented in this text, is broad enough to encompass many known dualities through a rich assortment of substantive theorems yet concrete enough to be used to generate an array of previously undiscovered dualities. This text will serve as a user manual for algebraists, for category theorists and for those who use algebra in their work, particularly mathematicians and computer scientists interested in non-classical logics. It will also give the specialist a complete account of the foundations, leading to the research frontier of this rapidly developing field. As the first text devoted to the theory of Natural Dualities, it provides an efficient path through a large body of results, examples and applications in this subject which is otherwise available only in scattered research papers. To enable the book to be used in courses, each chapter ends with an extensive exercise set. Several fundamental unsolved problems are included.
 

Pages sélectionnées

Table des matières

Dual Equivalences and Where to Find Them
1
1 Categories
2
2 Distributive lattices
7
3 Quasivarieties
15
4 Structured topological spaces
20
5 Predualities
29
Natural Dualities
39
2 Duality theorems
41
3 Piggyback dualities for varieties of Hey ting algebras
199
4 Restricted Priestley dualities
202
5 Piggyback dualities for varieties of Ockham algebras
207
6 Piggyback dualities for varieties of distributive palgebras
216
7 Completely dualisable quasivarieties
221
8 Endodualisable algebras
225
Optimal Dualities and Entailment
233
1 Test algebrasschizophrenia strikes again
234

3 Taming brute force with nearunanimity
52
4 Refining a duality via entailment
55
3 Strong Dualities
62
1 Full duality and the dual category
63
2 Strong duality and the role of injectivity
71
3 Producing strong dualities
79
Examples of Strong Dualities
94
2 Arithmetical strong dualities
98
3 NU strong dualities
102
4 Twoforone strong dualities
113
5 Vagrant dualities
116
Sample Applications
124
2 Endomorphism monoids and upside down lattices
125
3 Theory of algebraic and existential closure
129
4 Examples of algebraic and existential closure
135
5 Injectives weak injectives and absolute subretracts
144
6 Category equivalences
159
What Makes a Duality Useful?
171
1 Total structures and injectivity
173
2 Unary structures coproducts and nearunanimity
177
3 Better coproducts and logarithmicity
182
4 Exclusively unary structures and arithmeticity
186
Piggyback Dualities
192
2 Piggyback dualities for distributivelatticebased algebras
195
2 Entailment closure and the topology of failsets
238
3 Failsets and optimal dualities
240
4 Kleene algebras once again
246
5 The structure of failsets
251
6 Optimal dualities for varieties of distributive palgebras
261
Completeness Theorems for Entailment
270
2 Completeness of constructs for entailment
274
3 Local entailment
278
4 Optimal strong dualities and homentailment
281
the threeelement chain
286
Dualisable Algebras
291
2 Nearunanimity as an obstacle to duality
292
3 Some applications of the NU obstacle theorems
296
4 The balanced subalgebra method
299
5 The ghost element method
304
6 The termclosed subset method
309
7 Dualisable clones on a twoelement set
317
Algebras
325
Boolean Spaces
337
Bibliography
341
Notation
348
Index
350
Droits d'auteur

Expressions et termes fréquents

Références à ce livre

Informations bibliographiques