Question

I

which of these graphs are isomorphic?

Answer 1

To check the isomorphism of the graphs, there are four criteria as-

1) Equal number of vertices

2) Equal number of edges

3) Same degree of sequence (connected edges)

4) Equal number of circuit of particular length

Here, all the graphs have equal number of vertices i.e 6, have equal number of edges i.e 9, but degree of sequences are not same in all the graph as graphs a,b,c,d,e has 3 degree of sequence and in graph f has 4 degree of sequence. Again, minimum number of length of circuit is 3 in graphs a,d,e,f and in graphs b and c there are 4 minimum length of circuit.

Hence, set of isomorphic is {a, d, e} and {b, c}