Gerasimos “Gerry” Ladas is one of the most cited mathematicians in the world. The URI professor’s name and biography have been added to Thomson Scientific’s ISIHighlyCited.com, which honors researchers in 21 broad categories whose publications have received the highest number of citations worldwide.

His inclusion means that Ladas is among the 337 most cited mathematicians during the past 25 years. When one researcher cites another’s work, it is an acknowledgment of the relevance of the work to other studies.

Ladas joined URI’s Department of Mathematics in 1969. He is co-editor-in-chief of the Journal of Difference Equations and Applications and the associate editor of 13 other mathematics journals. He co-authored three undergraduate textbooks, six monographs, and more than 240 research papers. He is a referee for numerous journals and mathematics research proposals for the National Science Foundation, the U.S. Army Research Office, Research Corporation, and the National Sciences and Engineering Research Council of Canada.

Ladas focuses on the basic theory of difference equations so that other scientists can use his findings in a variety of applications. Difference equations, the professor explains, are about predicting the future state of a system in terms of the present and the past. He is currently on his third sabbatical at Harvard University’s School of Public Health, where he is consulting on biological mathematical models.

Ladas joins seven of his URI colleagues on the most-cited list: Psychologists Jim Prochaska, Joe Rossi, and Wayne Velicer; geoscientist Jean-Guy Schilling; plant and animal scientist Jeff Seemann, dean of the College of the Environment and Life Sciences; the late oceanographer and microbiologist John Sieburth; and electrical engineer Stephen Kay.