Graph
A graph G is an ordered pair V , E of sets V of vertices and E of edges, that are disjoint together with an incedence function ϕ : E V × V that associates with
Degree of a Vertex
Suppose that G = ( V , E ) is a graph, then we say that the degree of a vertex v is the number of other vertices connected to it with an edge. We define the syntax deg : V N 0 to be the function that maps a node to it's degree.
Sum of Degrees
Suppose that G is a finite graph, then we have that v V deg ( v ) = 2 | E |
Branching Factor
Suppose that we have a graph G , then we say that G has branching factor b N 1 , if every vertex has degree b
Average Branching Factor
Suppose that G is a finite graph, then the average branching factor of the graph is defined as v V deg ( v ) | V | Q
Maximum Branching Factor
Suppose that we have a graph G , then we say that G has a maximum branching factor of b N 0 , if every vertex has degree at most b
Path
A tuple ( v 1 , v 2 , v n ) V n is said to be a path if for every i [ 1 n 1 ] , { v i , v i + 1 } E .
Connected Vertices
Suppose that u , v V , then we say that u , v are connected if there is a path v 1 , v 2 , , v n where v 1 = u and v n = v
Connected Graph
Given a graph G we say that it is connected when for every u , v V , we have that u and v are connected.
A Graph with One Vertex is Connected
Suppose that G = ( V , E ) where V = { x } , then G is conntected.
Suppose that u , v V , then u = v = x , therefore the path x connects it to itself.
A Disconnected Graph is the Union of Many Disjoint Connected Subgraphs
Suppose that G is a disconnected graph, then G is the disjoint union of 2 or more connected subgraphs