Sivabal Sivaloganathan, chair of Waterloo's Department of Applied Mathematics from 2016 to 2023, and professor of Applied Mathematics from 1990 to present, passed away on March 2, 2025, after a brief illness.
Siv was a visionary mathematician, a dedicated mentor and a leading figure in the integration of mathematics and medicine. His groundbreaking contributions to continuum mechanics, biomechanics and mathematical oncology have left an enduring impact on applied mathematics and the biomedical sciences. During his career, Siv had an oversized impact on the Department of Applied Mathematics, the Faculty of Mathematics and the University of Waterloo.
Sivbal Sivaloganathan (1956-2025), Professor of Applied Mathematics, Chair, Department of Applied Mathematics, 2016-2023, Co-director, Fields Centre for Mathematical Medicine
"As chair of the Department of Applied Mathematics, long-time co-director of the Fields Centre for Mathematical Medicine, a Faculty of Mathematics Senator from 2022 to present and through many other contributions, Siv Sivaloganathan has shaped the Waterloo community in countless ways," says Mark Giesbrecht, Dean of Mathematics. "Beyond his professional achievements, Siv touched the lives of so many colleagues and students, many of whom considered him a dear friend."
Early years
Born in Sri Lanka, Siv spent his formative years in the UK, where he attended the British prep and public school system before pursuing his passion for mathematics at Oxford University. His journey took him from a postdoctoral research position at Oxford to a faculty role at the University of Alberta, before ultimately finding his academic home at the University of Waterloo.
Despite the initial cultural shift, Siv embraced Canada as his new home - a decision he never regretted. It was in Toronto that he met his wife, and together they built a life beyond academia, raising four children who now thrive in the US and Canada.
Pioneer in mathematical medicine research
Siv's research was deeply interdisciplinary, pioneering mathematical modeling of complex medical problems. His contributions to mathematical oncology were particularly influential, as he applied advanced computational and mathematical techniques to model cancer progression and treatment response. His work in biomechanics, including brain tissue modeling and hydrocephalus, provided new insights into cerebrospinal fluid dynamics and the mechanical properties of the brain, with critical implications for neurosurgery and medical imaging. His research also extended to high-intensity focused ultrasound (HIFU) as a cancer therapy, where his mathematical models played a pivotal role in refining treatment protocols.
Beyond his research, Siv was a dedicated mentor and educator, profoundly impacting his students. He supervised numerous graduate students and postdoctoral researchers, many of whom have gone on to successful careers in academia and industry. Known for his patience, generosity and ability to inspire curiosity, Siv had a rare gift for nurturing talent. Many of his former students credit him for shaping their careers and instilling a rigorous yet creative approach to problem-solving.
"Siv was an exceptional mentor, collaborator and friend. His dedication to excellence, his passion for discovery and his kindness have left an indelible mark on all of his students and postdocs," says Mohammad Kohandel, one of his close collaborators in the Department of Applied Mathematics. "He has touched the lives of many, sparking in us a drive to explore, innovate and excel. His ability to seamlessly blend rigorous mathematics with real-world applications has set a standard that will continue to inspire future generations of researchers."
Fields Centre for Mathematical Medicine and awards
Siv also played a pivotal role in advancing mathematical medicine through his leadership at the Fields Institute for Research in Mathematical Sciences, where he co-founded the Fields Centre for Mathematical Medicine and served as its long-time co-director. Under his guidance, the centre became a hub for interdisciplinary collaboration, bringing together mathematicians, clinicians and biomedical scientists to address pressing medical challenges.
He was a driving force behind several workshops and conferences on mathematical medicine, fostering collaborations that extended far beyond Canada. Siv was designated a University Research Chair 2011-2018, was named a Fellow of the Society for Mathematical Biology in 2022 and won the CAIMS-Fields Industrial Mathematics Prize in 2024.
Service to the University
Throughout his career, Siv has had a large influence on his department, the Faculty of Mathematics and the University. Among his many notable service contributions, he served as department chair for Applied Mathematics from 2016 to 2023. Before that, he served as the department's associate chair for graduate studies from 1994 to 2002. "Siv's generous and supportive style as a chair and a colleague were an inspiration to all of us in Applied Mathematics," says Hans De Sterck, the current chair of the department. "Siv was well-loved by students and colleagues alike, and his leadership has been instrumental in enhancing the research strength of the department through high-profile hiring and through building lasting connections with partners such as the Perimeter Institute for Theoretical Physics."
Siv was always a great champion of student and community life in the Faculty of Mathematics. For example, he was a great supporter of the Women in Mathematics (WiM) committee and their flagship Directed Reading Program, for which he was an advisory committee member and a proposal reviewer. "The WiM committee is deeply appreciative of Siv's contributions in advancing equity, diversity and inclusion," says Yu-Ru Liu, the current director of WiM. "Siv has been a trusted advisor to me with guidance related to WiM and broader academic life."
While department chair, Siv's contributions as a member of the Math Faculty's leadership team were also highly appreciated, as well as his contributions to the University as a Senator from 2022 until present.
Legacy
Siv Sivaloganathan's legacy will live on through the many lives he touched and the groundbreaking work he advanced. "Siv was a shining star in the Math Faculty, always cheerful and optimistic," says Alfred Menezes, a longtime colleague and friend. "He was a dear friend to many of us, as well as a mentor, teacher and research collaborator. He will be deeply missed."
