Obituary: Denis Louis Blackmore

By Aminur Rahman

Denis Louis Blackmore passed away on April 24, 2022, in Livingston, NJ. He was 78 years old. Denis was a mathematician who solved problems purely for the love of problem solving. He identified as neither a theoretical nor an applied mathematician and instead saw himself as part of both worlds. Denis traversed between a wide variety of fields with great ease and made contributions to topology, dynamical systems, bifurcation theory, physics, biology, and engineering. He was also well read in history, politics, and the humanities. He loved rock and roll (especially Bob Dylan), appreciated classic films and books, was conversational in several languages, and wrote with great eloquence. Denis was truly emblematic of a Renaissance man in the age of specialization.

Denis grew up in Queens, NY, where he was raised by his beloved mother Helma. He often spoke about how hard his mother worked to ensure that he could pursue his educational aspirations. Upon receiving the New Jersey section of the Mathematical Association of America’s (MAA) Distinguished Teaching Award, he wrote that “there is the incalculable debt I owe to my mother, Helma — my rock, my unconditional safe harbor and role model nonpareil.”

Once he finished secondary school, Denis attended the Polytechnic Institute of Brooklyn—now the New York University Tandon School of Engineering—and initially majored in mechanical and aerospace engineering. However, a course on complex analysis that was taught by Jane Cronin Scanlon sparked his interest in mathematics. Denis’s newfound love of the subject only grew, leading him to pursue a Ph.D. in mathematics at the Polytechnic Institute of Brooklyn under the advisement of Pincus Mendelson and Burton Lieberman. He defended his dissertation on “Flows about a Critical Point with a Single Zero Characteristic Root” [1-3] and received his Ph.D. in 1971.

After completing graduate school, Denis joined the faculty of the Department of Mathematics at the Newark College of Engineering—now part of the New Jersey Institute of Technology (NJIT)—which at the time was a predominantly teaching-focused department with a traditional mathematics curriculum. Denis and a few other like-minded colleagues who were equally dedicated to teaching and research founded the Center for Applied Mathematics and Statistics in 1986, then later established a Ph.D. program in applied mathematics that graduated its first students in 1997. NJIT’s Department of Mathematical Sciences continues to produce transformative research in applied mathematics and statistics, much of which can be attributed to the initiatives of Denis and his colleagues.

Denis remained a prolific researcher throughout his career. He published 234 scientific works that have been collectively cited almost 3,000 times, advised 10 Ph.D. students, and was a member of scores of dissertation committees. His work significantly impacted a wide variety of fields, such as computer-aided design [4], granular materials [12], fluid mechanics [9, 10], applied mathematics [6, 7], and mathematical physics [5].

Denis was always down to earth and exemplified humility. For instance, my M.S. student was performing a literature search for his thesis on computational sociology earlier this year. He mentioned that he “found a paper by someone at NJIT named Blackmore who does exactly what we need” [8]. He then asked if I knew him, as he couldn’t find Denis’s website. Denis had published the paper two decades before other researchers had even started thinking about computational sociology in this manner, and yet I was not aware of it until I embarked on a project in a similar area. This example exemplifies precisely the type of person that Denis was — quietly working on interesting problems that were ahead of their time without braggadocio or self-promotion.

Beyond his research, Denis was a dedicated teacher and an inspirational mentor. I was fortunate enough to experience both of these aspects. Denis had a unique teaching style, much of which influenced my own approach to teaching. He came to class without any notes or books and lectured completely from memory. Denis always knew what he wanted to discuss, but he did not preestablish a set of problems to work through. Rather, he wanted the problems, questions, and calculations to come directly from his students. He taught mathematics not as a calculative chore but as a philosophical framework.

Denis also actively worked towards promoting diversity, equity, and inclusion. He served as a mentor in the McNair Scholars Program and was as an investigator for an NSF-ENGAGE grant to increase the retention of those who were historically excluded in academia. He also joined the Newark Literacy Campaign in 1989 and was an active member until his death.

Denis received several awards that acknowledged his dedication to research and teaching, including the Harlan J. Perlis Research Award from NJIT in 1993, the NJIT Honors Program’s Excellence in Teaching Award in 1987, and the New Jersey section of MAA’s Distinguished Teaching Award in 2015. In addition, he served on editorial boards for the Journal of Nonlinear Mathematical Physics, Differential Equations & Applications, Regular and Chaotic Dynamics, and the Journal of Chemical Information and Computer Science. Denis was also the associate editor of Mechanics Research Communications. 

Throughout his career, Denis remained an active member of SIAM. In addition to publishing in SIAM journals [6, 7, 11], he regularly organized minisymposia at the biennial SIAM Conference on Applications of Dynamical Systems over the course of several decades. In fact, the dynamical systems meetings in Snowbird, Utah, were among his favorites to attend. I had the privilege of co-organizing minisymposia with Denis and our colleague Ivan Christov at the 2017, 2019, and 2021 iterations of the conference. Spending an entire week at Snowbird every two years discussing mathematical ideas, politics, history, and music—all while watching hockey at the Aerie—with Denis and our contemporaries from around the world will be sorely missed.

Outside of the mathematics world, Denis was a devoted husband and father. He is survived by his wife Diane—his partner of over 50 years—and their son John. Denis always spoke of the incredible amount of support that he received from Diane and John, and we as a community express our deepest condolences to them.

Denis has impacted countless students through his teaching and mentoring and made significant contributions to science that will last for centuries. He was also one of the kindest people that I have ever met and will be dearly missed by all who knew him.

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References
[1] Blackmore, D.L. (1971). Flows about a critical point with a single zero characteristic root. [Ph.D. thesis, Department of Mathematics, Polytechnic Institute of Brooklyn]. ProQuest Dissertations Publishing. 
[2] Blackmore, D.L. (1973). On the local normalization of a vector field at a degenerate critical point. J. Differ. Equ., 14(2), 338-359.
[3] Blackmore, D.L. (1974). An example of a local flow on a manifold. Proc. Am. Math. Soc., 42(1), 208-213.
[4] Blackmore, D., Leu, M.C., & Wang, L.P. (1997). The sweep-envelope differential equation algorithm and its application to NC machining verification. Comput. Aided Des., 29(9), 629-637.
[5] Blackmore, D., Samulyak, R., & Rosato, A. (1999). New mathematical models for particle flow dynamics. J. Nonlin. Math. Phys., 6(2), 198-221.
[6] Blackmore, D., & Ting, L. (1985). Surface integral of its mean curvature vector. SIAM Rev., 27(4), 569-572.
[7] Blackmore, D., & Zhou, J.G. (1996). A general fractal distribution function for rough surface profiles. SIAM J. Appl. Math., 56(6), 1694-1719.
[8] Chen, J., & Blackmore, D. (2002). On the exponentially self-regulating population model. Chaos, Solitons, Fract., 14(9), 1433-1450.
[9] Pillapakkam, S.B., Singh, P., Blackmore, D., & Aubry, N. (2007). Transient and steady state of a rising bubble in a viscoelastic fluid. J. Fluid Mech., 589, 215-252.
[10] Rahman, A., & Blackmore, D. (2020). Walking droplets through the lens of dynamical systems. Mod. Phys. Lett. B., 34(34), 2030009.
[11] Rahman, A., & Blackmore, D. (2022). The one-dimensional version of Peixoto’s structural stability theorem: A calculus-based proof. SIAM Rev. To appear.
[12] Rosato, A.D., Blackmore, D.L., Zhang, N., & Lan, Y. (2002). A perspective on vibration-induced size segregation of granular materials. Chem. Eng. Sci., 57(2), 265-275.

Aminur Rahman is an acting instructor (postdoctoral researcher) in the Department of Applied Mathematics at the University of Washington. His research involves formulating mechanistic models of real-world phenomena and analyzing them via dynamical systems theory, numerical methods, and data-driven techniques.