A clique of size K is a set of K vertices in which every two

In a set which has only one vertex, there are no pairs, so it is true by default.

By the way, cliques are usually only defined for simple graphs.

]]>In a previous post, it was said that evey graph has a clique of size one.

How come? as I understand it, for a graph to have a 1-clique it must has a loop. Am I right?

ant about k=0, every graph has a 0-clique right?

And another thing about Q6:

May we assume the graphs are simple? or maybe even that k>1?