On the Gracefulness of the Union of Mutually Non-intersecting Digraphs n·_3
Chunlong Li · Journal of Inner Mongolia University for the Nationalities · 2006
The Gracefulness of the union of four graphs consisting mutually non-intersecting digrapsh n·_3 and the gracefulness of the union of six graphs consisting mutually non-intersecting digraphs n·_3 are verified in this paper.We conjecture that union of mutually non-intersecting digraphs n·_3 of even number is graceful graph.