1. Ch. 9: Graph Theory
9.1 Intro to Graphs

2. Uses Degree of separation- Hollywood, acquaintance, collaborate-Erdos
Travel between cities
Konigsberg bridge
Shortest path
Least cost
Schedule exams, assign channels, rooms
Number of colors on a map
Highway inspecting, snow removal, street sweeping
Mail delivery
Niche overlap- ecology
Influence graphs
Round-robin tournaments
Precedence graphs

3. G=(V,E)
G=(V,E) where V is the set of vertices and E is the set of edges Terminology is not standard from book to book. Types of Graphs – see handout Simple G=(V,E) where E is the set of unordered pairs Multigraph Pseudo-graph Directed Graph G=(V,E) where E is the set of ordered pairs of edges Directed Multigraph

4. Simple and multigraph
Simple graph G=(V,E) where E is the set of unordered pairs
Multigraph

5. Pseudo and directed graphs
Pseudo-graph
Directed Graph G=(V,E) where E is the set of ordered pairs of edges

6. multigraph
Directed Multigraph