INFORMS Expository Writing Award

It is with great pleasure that the INFORMS Committee for the Expository Writing Award names the late Professor Uriel G. Rothblum of the Technion-Israel Institute of Technology as the recipient of its 2012 award.  Uriel Rothblum was the author or co-author of more than 160 journal articles addressing such diverse theoretical areas as linear algebra, optimization, dynamic programming, networks, economics, game theory, and applied probability as well as applications to problems found in homeland security and the management of competitive research and development.  In addition to these many journal publications, he co-authored (with Frank Hwang) the bookPartitions: Optimality and Clustering(World Scientific, 2012). 

Professor Rothblum’s most-cited paper is “Algebraic Eigenspaces of Nonnegative Matrices” (Linear Algebra and its Applications, 1975).  This paper generalizes the famous Perron-Frobenius theorem regarding the dominant eigenvalue of irreducible nonnegative square matrices toarbitrarynonnegative square matrices.  While deriving results in a paper this technical is difficult enough, communicating them clearly requires the careful, concise and precise writing for which Professor Rothblum is known.

An insightful marriage of theory and application is Professor Rothblum’s beautifully written paper with Alvin Roth entitled “Truncation Strategies in Matching Markets – In Search of Advice for Participants” (Econometrica, 1999).  Models of matching markets such as those that pair medical residents with hospitals suggest that some residents could improve their individual outcomes by misrepresenting their true preferences.  The curious result of this article is that when participants know little about the preferences of others, a good strategy to employ is truncation – that is, restrict the number of positions reported to something lower than the true number acceptable, but truthfully rank those positions that are reported.  This paper is structured by moving from a description of matching markets, to a basic model, to a series of cleverly constructed “toy problems”, and finally to several clearly stated theorems together with a summary discussion.  In this way, the paper successfully makes its points while heightening reader interest along the way.

Professor Rothblum was also interested in the relationship between optimal solutions in centralized resource allocation problems, and the corresponding equilibria in decentralized versions of the same resource allocation problems.  Through the clever use of a system of linear penalties and rewards, Rothblum developed a method by which one could create a game whose equilibrium solution would correspond with the desired centralized optimal solution and thus coordinate the players in the game.  This approach was detailed in his paper with Boaz Golany, “Inducing Coordination in Supply Chains through Linear Reward Schemes” (Naval Research Logistics, 2006).  The idea is illustrated via a series of clearly and crisply written examples.

An innovative application of this idea in a dynamic setting appears in “A Generalized Two-Agent Location Problem:  Asymmetric Dynamics and Coordination” (Journal of Optimization Theory and Applications, 2011, with Golany and Konstantin Kogan).  This paper shows how two patrolling agents can coordinate their movement over time to achieve some objective without requiring a centralized controller that yields equivalent results to those that could be achieved via centralized control.  The results qualify as superb while the paper itself unfolds like an adventure story.

From his earliest contributions until his untimely death in March of this year, Professor Rothblum tackled very difficult problems in both theoretical and applied mathematics and operations research, yet his writing was always patient and clear.  His work exemplifies the art of technical writing, and has been very influential in both theory and applications.  For these reasons, the Expository Writing Committee (Richard Steinberg, Edward H. Kaplan and Dimitris Bertsimas) is pleased to name Uriel G. Rothblum as the recipient of the 2012 INFORMS Expository Writing Award.