Jeannette Janssen

Jeannette Catharina Maria Janssen is a Dutch and Canadian mathematician whose research concerns graph theory and the theory of complex networks. She is a professor of mathematics at Dalhousie University, the chair of the Dalhousie Department of Mathematics and Statistics,^[1] and the chair of the Activity Group on Discrete Mathematics of the Society for Industrial and Applied Mathematics.^[2]

Education and career

Janssen earned a master's degree at the Eindhoven University of Technology in 1988.^[3] She completed her Ph.D. at Lehigh University in 1993. Her dissertation, Even and Odd Latin Squares, concerned Latin squares and was supervised by Edward F. Assmus Jr.^[3][4]

From 1988 to 1990 Janssen was a lecturer at the Universidad de Guanajuato in Mexico. After completing her Ph.D., she became a postdoctoral researcher jointly at the Laboratoire de Combinatoire et d’Informatique Mathématique of Université du Québec à Montréal and at Concordia University. She took a position as a lecturer and research associate at the London School of Economics in 1995, and moved to Acadia University in 1997 before taking her present position at Dalhousie University.^[3]

At Dalhousie, she was named department chair in 2016, becoming the first female chair of the mathematics department.^[1]

Service

Janssen directed the Atlantic Association for Research in the Mathematical Sciences from 2011 to 2016, and chairs its board of directors.^[5] She was elected as chair of the Activity Group on Discrete Mathematics (SIAG-DM) of the Society for Industrial and Applied Mathematics (SIAM) for the 2021–2022 term.^[2]

Research

In a 1993 paper, Janssen solved the unbalanced case of the Dinitz conjecture, showing that any partial Latin rectangle could be extended to a full rectangle. The problem is equivalent to list edge-coloring of complete bipartite graphs, and her solution was based on earlier work on list coloring by Noga Alon and Michael Tarsi. Janssen's work "surprised even many of the experts",^[6] and was considered to be "great progress" on the Dinitz conjecture. The remaining case of the conjecture for squares (balanced complete bipartite graphs) was proven a year later by Fred Galvin.^[7]