Induced Subgraph by V'
Complete graph
eg.
if (v,w) is an edge then v & w are adjacent to each other and v
and w are said to be incident with the edge (v,w).
def A path from v to w is a sequencs of vertex
,..., such that 
.
(Books defenition is not good)
If all 
are distinct,
then the length of the path is k.
is a path of length 0.
Connected Graph:
Cycle is path 
such that 
A graph without any cycle is called acylic.
Tree: Acyclic connected graph
Rooted tree has a designated root vertex establishing parent & child
relationship
number of edge in a tree is n-1
Could be proved by induction
A connected component of a graph G is a maximal connected subgraph of G
Weighted Graph
G=(V,E,w)
w(e) weight of e (Capacity or distance)