MINIMAL EDGE EXTENSIONS OF SOME PRECOMPLETE GRAPHS
We consider the minimal edge k-extensions of precomplete graphs - graphs in which there is a vertex adjacent to all other vertices. The lemma about the marginal value of k when a precomplete graph can have a minimal edge k-extension is proved. The full description of all the minimal edge k-extensions of precomplete graphs being joins of a complete graph and an empty graph, a chain or a cycle is given