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The ¶®É«µÛ banner is flying at half-mast from July 18–21, 2022 in remembrance of Dr. Joseph Wai Hung So, Professor Emeritus in the Department of Mathematical & Statistical Sciences, Faculty of Science.

Joseph was a member of the department for close to three decades. After undergraduate studies at the University of Hong Kong, Joseph completed Master's and PhD degrees at the ¶®É«µÛ. He defended his PhD thesis with the title "A study on some one- and two- loci predator-prey interaction models" in 1984 under the supervision of Herbert Freedman.

After a term assistant professorship at Emory University, Joseph joined our Department as an assistant professor in 1987 and was a faculty member until his retirement in 2010. Joseph was a key member of the differential equation and dynamics group, and his research was a significant factor for the group to be internationally known. Joseph made many fundamental contributions to mathematical biology, differential equations and dynamical systems. Earlier work of Joseph’s made important contributions to the problem of persistence which was a very active area of mathematical biology in the 80s and 90s. His 1989 joint paper with J. Hofbauer on the criteria of uniform persistence for general biological systems is still widely quoted today. Another joint paper with J. Hofbauer in 1994 made a breakthrough in the problem of co-existing limit cycles for 3-dimensional Lotka-Volterra (L-V) systems, by constructing for the first time a concrete system with two coexisting limit cycles. The result and several questions raised in the paper stimulated much research activities and results on the number of co-existing limit cycles of the L-V systems, with a complete solution given 15 years later in 2009. His collaborations with Jianhong Wu in the late 90s made fundamental contributions to the theory of partial differential equations with delays and established one of the earlier results on the existence and smoothness of center manifold for such systems. In the 2000s, Joseph published several influential papers on nonlocal reaction-diffusion equations with time delays, including existence and stability of travelling waves.

Joseph had a warm heart and was always ready to help others. As many of us who knew Joseph would remember, if you asked him a question and he didn’t have an answer right away, you would receive an email in the evening from him with a perfect answer. Joseph was an original and true fan of Mac computers, playing a Yamaha keyboard with a Mac, years before OSX came up with the Garageband. He got to indulge his love of music and art after his retirement, playing in a Chinese folk music band and taking up photography.

We express our deepest sympathy to Joseph’s family and friends and he will be dearly missed by his colleagues in the department.

For information about lowering the ¶®É«µÛ banner, visit the In Memoriam webpage.