Module 1 Flashcards
Graph
Let V be a finite non empty set and E be the subset of VxV then G=(V,E) is called a Graph, where V is the set of vertices and E is the set of Edges
Trvial Graph
graph with a single vertex
Null(empty Graph)
No edges
Isolated Vertex
a Vertex that is not adjacent to any other vertex
Parallel edge
in a graph G=(v,e) if more than one edge is associated with a pair of vertices than these edges are called parallel edge
Order and Size
If G=(V,E) be a finite grapgh where V(G) denotes the number of vertices in G and is called Order of that graph and E(G) denotes number of Edges in G and is called the size of G
ie
order = number of vertices
size = number of edges
Simple Graph
Graph with no self loops or parallel edges
Incidence on graph
When a vertex vi is the end vertex of edge ei then ei and vi are said to be incident with each other
adjacent vertex
two vertices are said to be adjacent if they are the end vertices of the same edge
degree of a vertex
no of edges connected to it (self loop is counted twice)
InDegree of a vertex
Number of edges coming into the vertex
OutDegree of a vertex
Number of edges going out of the vertex
No of edges in a graph (HS theorem)
sum of degree of each vertex
terminal vertex(end vertex)
the vertex that the arrow is pointed too
Initial vertex
the vertex from which the arrow is pointed from
Complete Graph(Kn)
its a simple graph in which there is exactly one edge b/w each pair of distinct vertices in it
number of edges in kn
nC2 (n(n-1)/2)
Cycle (Cn)
It’s a path that starts from one vertex and ends at the same vertex
Wheel(Wn)
Obtained by adding a additional vertex to a cycle
Bipartite Graph
Its a graph in which the vertex set of v is partioned into 2 disjoint sets (v1 and v2) such that every edge in the graph connects a vertex in v1 and a vertex in v2 (making sure no edge in the graph connects to vertices of the same set aka v1 or v2).
Complete bipartite graph
its a bipartite graph in which each vertex in the set v1 connects to every vertex in the vertex set v2
Walk
its an alternating sequnce of vertices and connecting edges its the route from one vertex to another or from a vertex back to itself (vertices or edges can be repeated)
length of walk
number of edges in the walk
Trail
A walk that does not repeat any edges.
Path
A trail that does not repeat any vertices.
Cycle
A closed walk that does not repeat any edges.
Connected Graph
if there is a path b/w every pair of vertices in a graph
Disconnected
if there isnt a path b/w every pair of vertices in a graph
components
a disconnected graph consists of 2 or more connected graphs and each of these are called components
Regular Graph
If every vertex of a graph has the same degree then its called a regular graph