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Graph Theory

A comprehensive reference covering graph theory from elementary definitions through structural theory, algorithms, algebraic methods, probabilistic models, computational complexity, and modern applications in fourteen parts with appendices.

Graph Theory Reference

Part I. Foundations of Graph Theory

ChapterTitle
1What Graph Theory Is
2Basic Definitions
3Vertices and Edges
4Graph Representations
5Degree of a Vertex
6Walks, Trails, and Paths
7Cycles and Circuits
8Connected Graphs
9Components
10Isomorphism
11Subgraphs
12Graph Operations
13Complement Graphs
14Graph Invariants
15Classes of Graphs

Part II. Directed and Weighted Graphs

ChapterTitle
16Directed Graphs
17In-Degree and Out-Degree
18Directed Paths and Cycles
19Strong Connectivity
20Directed Acyclic Graphs
21Topological Ordering
22Weighted Graphs
23Multigraphs
24Hypergraphs
25Signed and Labeled Graphs

Part III. Trees and Forests

ChapterTitle
26Trees
27Forests
28Rooted Trees
29Binary Trees
30Spanning Trees
31Minimum Spanning Trees
32Prüfer Sequences
33Tree Traversal
34Tree Decomposition
35Applications of Trees

Part IV. Planar and Geometric Graphs

ChapterTitle
36Planar Graphs
37Plane Embeddings
38Euler’s Formula
39Faces and Regions
40Kuratowski’s Theorem
41Graph Coloring of Planar Graphs
42Dual Graphs
43Geometric Graphs
44Intersection Graphs
45Computational Geometry Connections

Part V. Connectivity and Network Structure

ChapterTitle
46Vertex Connectivity
47Edge Connectivity
48Cuts and Cut Sets
49Bridges and Articulation Points
50Menger’s Theorem
51Network Reliability
52Expansion and Expanders
53Graph Separators
54Sparse and Dense Graphs
55Random Walks on Graphs

Part VI. Matching and Covering

ChapterTitle
56Matchings
57Perfect Matchings
58Hall’s Marriage Theorem
59Bipartite Matching
60Maximum Matching Algorithms
61Vertex Covers
62Edge Covers
63Independent Sets
64Cliques
65Dominating Sets

Part VII. Coloring Theory

ChapterTitle
66Vertex Coloring
67Edge Coloring
68Chromatic Number
69Chromatic Polynomial
70Greedy Coloring
71Brooks’ Theorem
72Perfect Graphs
73Ramsey Theory
74List Coloring
75Fractional Coloring

Part VIII. Algebraic Graph Theory

ChapterTitle
76Adjacency Matrices
77Incidence Matrices
78Laplacian Matrices
79Spectrum of a Graph
80Eigenvalues and Eigenvectors
81Spectral Theorems
82Algebraic Connectivity
83Expander Graphs
84Graph Energy
85Cayley Graphs
86Automorphism Groups

Part IX. Probabilistic and Random Graphs

ChapterTitle
87Random Graph Models
88Erdős-Rényi Graphs
89Threshold Phenomena
90Small-World Networks
91Scale-Free Networks
92Preferential Attachment
93Percolation on Graphs
94Probabilistic Methods
95Random Processes on Networks

Part X. Graph Algorithms

ChapterTitle
96Graph Traversal Algorithms
97Breadth-First Search
98Depth-First Search
99Shortest Paths
100Dijkstra’s Algorithm
101Bellman-Ford Algorithm
102Floyd-Warshall Algorithm
103Network Flow
104Maximum Flow Algorithms
105Minimum Cut Algorithms
106Matching Algorithms
107Union-Find Structures
108Dynamic Graph Algorithms
109Approximation Algorithms
110Randomized Algorithms

Part XI. Computational Complexity

ChapterTitle
111Complexity Classes
112NP-Complete Graph Problems
113Hamiltonian Paths and Cycles
114Traveling Salesman Problem
115Graph Isomorphism Problem
116Parameterized Complexity
117Fixed-Parameter Tractability
118Approximation Hardness

Part XII. Advanced Topics

ChapterTitle
119Extremal Graph Theory
120Turán-Type Problems
121Szemerédi Regularity Lemma
122Minor Theory
123Robertson-Seymour Theory
124Infinite Graphs
125Topological Graph Theory
126Category-Theoretic Graphs
127Simplicial Complexes
128Graph Limits
129Temporal Graphs
130Quantum Graph Theory

Part XIII. Applications

ChapterTitle
131Social Networks
132Web Graphs
133Search Engines and PageRank
134Biological Networks
135Chemical Graph Theory
136Electrical Networks
137Transportation Networks
138Communication Networks
139Compiler Dependency Graphs
140Knowledge Graphs
141Recommendation Systems
142Machine Learning on Graphs
143Graph Neural Networks
144Distributed Systems
145Blockchain and Peer-to-Peer Networks

Part XIV. Specialized Structures

ChapterTitle
146Bipartite Graphs
147Complete Graphs
148Regular Graphs
149Interval Graphs
150Chordal Graphs
151Comparability Graphs
152Perfect Graphs
153Tournament Graphs
154Grid Graphs
155De Bruijn Graphs
156Kneser Graphs
157Petersen Graph
158Ramanujan Graphs

Appendices

AppendixTitle
ASet Theory and Relations
BProof Techniques
CLinear Algebra for Graph Theory
DProbability Review
EAlgorithms and Complexity
FMathematical Notation
GHistorical Development
HCommon Graph Families
ITheorem Index
JSymbol Index

This structure moves from elementary graph concepts toward structural theory, algorithms, algebraic methods, probabilistic models, and modern applications. It supports both pure mathematical treatment and computational graph systems used in computer science, networks, optimization, and machine learning.

I. Foundations of Graph TheoryBasic definitions, vertices and edges, graph representations, degree, walks, paths, cycles, connectivity, isomorphism, subgraphs, and classes of graphs — the bedrock of graph theory.
15 pages · 135 min
II. Directed and Weighted GraphsDirected graphs, in-degree and out-degree, directed paths and cycles, strong connectivity, DAGs, topological ordering, weighted graphs, multigraphs, hypergraphs, and labeled graphs.
10 pages · 103 min
III. Trees and ForestsTrees, forests, rooted and binary trees, spanning trees, minimum spanning trees, Prüfer sequences, tree traversal, tree decomposition, and applications of trees.
10 pages · 89 min
IV. Planar and Geometric GraphsPlanar graphs, plane embeddings, Euler's formula, faces, Kuratowski's theorem, coloring of planar graphs, dual graphs, geometric graphs, and connections to computational geometry.
10 pages · 76 min
V. Connectivity and Network StructureVertex and edge connectivity, cuts, bridges, articulation points, Menger's theorem, network reliability, expanders, separators, and random walks on graphs.
10 pages · 95 min
VI. Matching and CoveringMatchings, perfect matchings, Hall's marriage theorem, bipartite matching, maximum matching algorithms, vertex and edge covers, independent sets, cliques, and dominating sets.
10 pages · 80 min
VII. Coloring TheoryVertex and edge coloring, chromatic number, chromatic polynomial, greedy coloring, Brooks' theorem, perfect graphs, Ramsey theory, list coloring, and fractional coloring.
10 pages · 79 min
VIII. Algebraic Graph TheoryAdjacency, incidence, and Laplacian matrices, graph spectrum, eigenvalues and eigenvectors, spectral theorems, algebraic connectivity, expander graphs, graph energy, Cayley graphs, and automorphism groups.
6 pages · 63 min
IX. Probabilistic and Random GraphsRandom graph models, Erdős-Rényi graphs, threshold phenomena, small-world and scale-free networks, preferential attachment, percolation, probabilistic methods, and random processes on networks.
0 pages · 0 min
X. Graph AlgorithmsGraph traversal, BFS, DFS, shortest paths, Dijkstra, Bellman-Ford, Floyd-Warshall, network flow, maximum flow, minimum cut, matching algorithms, union-find, dynamic graph algorithms, approximation, and randomized algorithms.
0 pages · 0 min
XI. Computational ComplexityComplexity classes, NP-complete graph problems, Hamiltonian paths and cycles, the traveling salesman problem, graph isomorphism, parameterized complexity, fixed-parameter tractability, and approximation hardness.
0 pages · 0 min
XII. Advanced TopicsExtremal graph theory, Turán-type problems, Szemerédi regularity lemma, minor theory, Robertson-Seymour theory, infinite graphs, topological and category-theoretic graph theory, simplicial complexes, graph limits, temporal graphs, and quantum graph theory.
0 pages · 0 min
XIII. ApplicationsSocial networks, web graphs, PageRank, biological and chemical networks, electrical and transportation networks, compiler graphs, knowledge graphs, recommendation systems, graph neural networks, distributed systems, and blockchain networks.
0 pages · 0 min
XIV. Specialized StructuresBipartite, complete, and regular graphs, interval and chordal graphs, comparability and perfect graphs, tournaments, grid graphs, De Bruijn graphs, Kneser graphs, the Petersen graph, and Ramanujan graphs.
0 pages · 0 min
AppendicesReference material: set theory and relations, proof techniques, linear algebra for graph theory, probability review, algorithms and complexity, mathematical notation, historical development, common graph families, theorem index, and symbol index.
0 pages · 0 min