Originally Posted by

**jaidon** A simple graph G is self-complimentary. Show there exists an integer k such that the order of G = 4k or 4k+1.

I'm feeling a tad lost on this. I understand the idea of self-complimentary. G and its compliment will be isomorphic and have the same deg sequence, order, size.

I have a feeling that the relation between the compliment, G and a complete graph will come in handy ie) the compliment of G= k -E(G) where k here should have subscript n for complete graph, this is a different k than in the question.

Any thoughts on this would be appreciated.