A graph with p vertices is said to be strongly multiplicative if its
vertices can be labelled 1; 2; : : : ; p so that the values on the edges, obtained
as the product of the labels of their end vertices, are all distinct.
In this paper, we study structural properties of strongly multiplicative
graphs. We show that all graphs in some classes, including all trees,
are strongly multiplicative, and consider the question of the maximum
number of edges in a strongly multiplicative graph of a given order.
Keywords: graph labelling, multiplicative labelling.
2000 Mathematics Subject Classification: 05C78.