John (“Jody”) David Trout Jr., an associate professor of mathematics, died on Sept. 9. For more than three decades, Trout was a fixture of the Dartmouth math department, a specialist in abstract mathematics who kept his door open to anyone who wanted to talk.
“Jody gave his whole career to Dartmouth and to his students and colleagues, and the math department was in every sense his home,” said Interim Dean of Faculty John Carey. “He had a rare gift for making intimidating ideas feel accessible, and for treating everyone who walked into his office, student or colleague, as someone worth his full attention.”
Trout grew up in Moncks Corner, South Carolina, and studied mathematics at the College of Charleston, graduating magna cum laude in 1986. He earned a master’s degree at Clemson University in 1988 and a doctorate at the Pennsylvania State University in 1995, working under Paul Baum and Nigel Higson. He came to Dartmouth that same year as an assistant professor and was promoted to associate professor in 2001.
His research was in functional analysis and operator algebras, and specifically in noncommutative geometry, which studies spaces where the ordinary rule that a times b equals b times a no longer holds. Non-commuting arithmetic underlies quantum mechanics, and Trout was drawn to that seam between deep abstraction and the physics of the very small. His work focused on pure mathematics, while the questions that drove him came from physics.
Trout published nearly a dozen papers in major research journals. In 2000, with Higson and his frequent collaborator Erik Guentner, he wrote a monograph on equivariant E-theory that appeared in the Memoirs of the American Mathematical Society and is still widely cited. Two years earlier, with Higson and the operator theorist Gennadi Kasparov, he had proved a Bott periodicity theorem for infinite-dimensional Euclidean space, published in Advances in Mathematics. Grants from the National Science Foundation supported his work on index theory, elliptic operators, and E-theory across more than a decade. That work took him abroad: in 1999, at the invitation of the Peruvian Congress’s commission on science and technology, Trout lectured in Lima on the index theory of elliptic operators, and one of the talks was broadcast on Peru’s congressional news channel.
Dana Williams, the Benjamin P. Cheney Professor of Mathematics, Trout’s longtime colleague and collaborator, remembers a dedicated teacher who was popular with undergraduates and graduate students alike. Trout developed Math 66, Mathematical Topics in Modern Physics, and taught it many times over the past decade. He co-developed an interdisciplinary course, Mathematics and Science Fiction, and in recent years regularly taught Metric Spaces and Measure Theory, which included both undergraduate and graduate students. He advised undergraduate honors theses, sat on many dissertation committees over the years, and guided two doctoral students to their degrees, Oscar Campos, Guarini ’07, and Matt Mahoney, Guarini ’09.
Mahoney, now a principal computational scientist at The Jackson Laboratory, was unsure of his academic focus and had never taken a course with Trout when he walked into Trout’s office to ask whether he was taking students. Trout said yes, went to the chalkboard, and started sketching out a research problem on the spot.
“In beautiful cursive handwriting, he gave an impromptu, hour-long lecture on this arcane topic, with a wry smile on his face, stopping to point out when one technique or another connected to deep facts in quantum physics or won somebody a Fields medal,” Mahoney recalls. “From that day on, this was how my meetings with Jody went. I would show up and we would have a breezy chat about deep ideas. Every week I looked forward to our working time together.”
“Over time, as my skills and confidence improved, I took over at the chalkboard,” Mahoney said. “All the while, he patiently guided me toward a dissertation I look back on with pride. I will always remember Jody for his kindness, for taking me as a student when I was a little lost, and helping me become who I am today.”
Dimitrios Giannakis, chair of the math department and the Jack Byrne Professor of Mathematics, came to Dartmouth in 2021 as an applied mathematician whose interests ran adjacent to Trout’s. “The numerous conversations we had over the years deepened my understanding of these fields and influenced my research,” Giannakis said. Trout gave what Giannakis remembers as “beautiful talks” in the department’s functional analysis seminar, sometimes with handouts that Giannakis still keeps pinned to his office notice board. When Giannakis knocked with a question, Trout was always happy to talk. “If the answer was not immediately known to him,” Giannakis said, “I knew I was likely dealing with a hard problem.”
Trout loved pop culture as much as he loved the universe’s big ideas, as ready to talk through the latest plot twist on Lost or Battlestar Galactica as the newest result in physics. He hosted watch parties for season finales where graduate students stayed for hours afterward, playing games on the full-size arcade machine in his basement.
Trout also had a gift for talking about mathematics with people who were not mathematicians. For years he gave public lectures he called the Fourth Dimension, inspired by Flatland, a Victorian novella about a two-dimensional world reckoning with the existence of dimensions beyond its own. He used that premise to walk audiences toward the harder question of what a fourth spatial dimension might look like. He gave these talks to the Dartmouth Mathematical Society, which he was closely involved with for many years, and at venues in the Upper Valley. He also reviewed science fiction novels for the Notices of the American Mathematical Society and wrote an essay on the mathematics of Op Art for a Hood Museum of Art catalog.
Tracy Moloney, who worked as the math department’s administrator for more than two decades, recalls a colleague who gave people his full attention. “He was a phenomenal listener, and he always had his door open,” she said. A serious injury years earlier had left Trout with lasting mobility challenges, but it never kept him away. Colleagues remember watching him take the stairs instead of the elevator, and marveling at his determination.
Above all, Trout was a devoted father to his two children, Natalie and Kyprian. “His children were the light of his life,” Moloney said.
He was active in the Orthodox Christian church, at Holy Resurrection Orthodox Church in Claremont, and he shared his love of astronomy with his family.
Moloney also recalls how Trout loved the holidays. In the years before he married, Moloney said, he often spent them at her family’s table. “Math and Jody were my other family,” she said, "and my personal family was also Jody’s family. He had family in many different ways, and that mattered to him.”
Trout is survived by his children, Natalie and Kyprian, and his wife, Deanne.
Details about a memorial gathering will be announced. The Dartmouth flag will be lowered in Trout’s honor on Monday, Sept. 21, and Tuesday, Sept. 22.