User:Murugan/tnou

A graph is an ordered triple (V,E,f) where V is a non-empty set,E is a set disjoint with V and fis the incidence function. Now consider V={1,2,3,4},E={a,b,c,d,e,g} and f as follows: f(a)= (1,2) f(b)= (2,3) f(c)= (3,4) f(d)= (4,1) f(e)= (1,3) f(g)= (2,4) This is a simple graph since it has no loops and multiple edges.So, What is a loop? What is a loop? What is link? To define these ,we need a few basic definitions. The elements of V are called vertices, The elements of V are called edges; 1,2 are called the ends of the edge a;Also we say a joints 1 and 2. An edge with the same end vertices is called a loop and an edge with different end vertices is called a link. What is a multiple edge?