1994 Hall Medal awarded to Ortrud Oellerman
From BICA (15) 1995:
The 1994 Hall Medals of the ICA
The Hall Medals of the ICA are awarded to Fellows of the Institute who have not passed age 40 and who have already produced a distinguished corpus of significant research work. The Hall Medals were inaugurated in 1994, and the 1995 Hall Medals, the first to be granted, have been awarded to Ortrud Ruth Oellerman, Christopher Andrew Rodger, and Douglas Robert Stinson. We herewith give summaries of the much more extensive citations and publication lists that were supplied by the nominators of these three scholars.
After a master's degree at the University of Natal, in Durban, South Africa, under the direction of Henda Swart, Ortrud Oellerman completed her doctorate at Western Michigan University under Gary Chartrand. After five years on the faculty at the University of Natal, she followed her husband, who is a medical doctor, to Canada and now holds an adjunct appointment at Brandon University. She has contributed to many aspects of graph theory: Eulerian graph theory, embedding and decomposition of graphs, aspects of uniformity and regularity, and measures of vulnerability. Notwithstanding the breadth of her research, she has obtained results of great depth, especially in the fields of Steiner distance and connectivity. (On the lighter side, we might mention that Ortrud is probably the only member of the ICA who speaks Zulu.)
Ortrud is currently the leading authority on Steiner distances in graphs and, under her guidance and leadership, a solid body of work has been completed which establishes a firm foundation for further research. The Steiner problem has important applications in phylogeny and in interprocessor communication in multiprocessor computers. Ortrud initiated the study of "eccentricity measures" with respect to Steiner distances, and has done fundamental work on many related concepts such as Steiner n-eccentricity, the Steiner n-centre of a graph, the Steiner n-distance of a vertex v in a graph, and k-Steiner distance hereditary graphs. More recently, she has initiated the study of the average n-Steiner distance of a connected graph of order p and has obtained a very efficient algorithm for finding the averagc Steiner n-distance of a tree.
Ortrud has also made valuable contributions to the study of the vulnerability of networks, and has investigated k-connectivity functions of graphs, aspects of integrity, n-domination theory, and algorithmic graph theory. Her research is of high quality, innovative, and original. She has been instrumental in developing fundamental theories for new concepts on which other researchers continue to build. In more than sixty papers, she has displayed power and innovation in obtaining new techniques.