1. Graph Vocabulary

2. Basic Vocabulary Vertex – a point
Edge – a line (not necessary straight) that connects two vertices
Graph – A collections of vertices and edges
Digraph – A graph with edges that have a direction

3. Connected
A graph is connected if there is a path between every pair of vertices
May have to use more than one edge and pass though other vertices to joint the two vertices
Connected
Not Connected

4. Adjacent Two vertices that have an edge connecting them are adjacent
Vertices A and C and A and D are adjacent
Vertices A and B and A and E are not adjacent

5. Complete A Graph where every point is adjacent to all other points
Not Complete

6. Graphs may look different but be the same.
If the graphs have the same vertices and the same edges then they are the same
They are all the same
graph

7. Set notation and Adjacency matrix
Two ways to describe a graph
Adjacency matrix – A square matrix with the vertices as both the row and column labels. With 1 if the two vertices are adjacent and 0 everywhere else.
Set Notation (Two parts)
Set of vertices
{P,Q,R,S,T,U,V}
Set of edges
{PQ,PU,QR,QV,UV,UT,VS,TS,RS}