Atnaujinkite slapukų nuostatas

Graphs and Homomorphisms [Kietas viršelis]

(, Charles University, Prague, The Czech Republic), (, Simon Fraser University, Burnaby, B.C., Canada)
Kitos knygos pagal šią temą:
Kitos knygos pagal šią temą:
This is a book about graph homomorphisms. Graph theory is now an established discipline but the study of graph homomorphisms has only recently begun to gain wide acceptance and interest. The subject gives a useful perspective in areas such as graph reconstruction, products, fractional and circular colourings, and has applications in complexity theory, artificial intelligence, telecommunication, and, most recently, statistical physics.

Based on the authors' lecture notes for graduate courses, this book can be used as a textbook for a second course in graph theory at 4th year or master's level and has been used for courses at Simon Fraser University (Vancouver), Charles University (Prague), ETH (Zurich), and UFRJ (Rio de Janeiro).

The exercises vary in difficulty. The first few are usually intended to give the reader an opportunity to practice the concepts introduced in the chapter; the later ones explore related concepts, or even introduce new ones. For the harder exercises hints and references are provided.

The authors are well known for their research in this area and the book will be invaluable to graduate students and researchers alike.
Introduction
1(36)
Graphs, digraphs, and homomorphisms
1(2)
Homomorphisms preserve adjacency
3(3)
Homomorphisms generalize colourings
6(4)
The existence of homomorphisms
10(6)
Homomorphisms generalize isomorphisms
16(2)
Homomorphic equivalence
18(2)
The composition of homomorphisms
20(7)
Homomorphisms model assignments and schedules
27(6)
Remarks
33(1)
Exercises
34(3)
Products and retracts
37(44)
The product
37(3)
Dimension
40(3)
The Lovasz vector and the Reconstruction Conjecture
43(3)
Exponential digraphs
46(1)
Shift graphs
47(3)
The Product Conjecture and graph multiplicativity
50(7)
Projective digraphs and polymorphisms
57(1)
The retract
58(2)
Isometric trees and cycles
60(4)
Reflexive absolute retracts
64(4)
Reflexive dismantlable graphs
68(4)
Median graphs
72(4)
Remarks
76(2)
Exercises
78(3)
The partial order of graphs and homomorphisms
81(28)
The partial orders C and Cs
81(1)
Representing ordered sets
82(3)
Incomparable graphs and maximal antichains in Cs
85(4)
Sparse graphs with specified homomorphisms
89(4)
Incomparable graphs with additional properties
93(1)
Incomparable graphs on n vertices
94(2)
Density
96(2)
Duality and gaps
98(3)
Maximal antichains in C
101(1)
Bounds
102(4)
Remarks
106(1)
Exercises
107(2)
The structure of composition
109(33)
Introduction
109(1)
Rigid digraphs
109(6)
An excursion to infinity
115(2)
The replacement operation
117(5)
Categories
122(6)
Representation
128(4)
A combinatorial obstacle to representation
132(3)
Some categories are not rich enough
135(3)
Remarks
138(1)
Exercises
139(3)
Testing for the existence of homomorphisms
142(50)
The H-colouring problem
142(1)
Dichotomy for graphs
143(8)
Digraph homomorphisms and CSPs
151(10)
Duality and consistency
161(5)
Pair consistency and majority functions
166(4)
List homomorphisms and retractions
170(8)
Trigraph homomorphisms
178(5)
Generalized split graphs
183(3)
Remarks
186(1)
Exercises
187(5)
Colouring---variations on a theme
192(30)
Circular colourings
192(8)
Fractional colourings
200(10)
T-colourings
210(2)
Oriented and acyclic colourings
212(6)
Remarks
218(1)
Exercises
219(3)
References 222(17)
Index 239