R. Keith Dennis

R. Keith Dennis March 10, 1944 – December 12, 2024 R. Keith Dennis, 80, a titan in mathematics and benefactor to Cornell and the greater Ithaca, NY community, died on December 12, 2024, following a prolonged battle with metastatic prostate cancer. He was known and loved for his quirky personality and sense of humor. Born in Vernon, TX, to parents Johnnie Fred and Maggie Dennis, (Roger) Keith grew up on a rural farm in Quanah, TX, and showed a dynamic aptitude and passion for mathematics from an early age. His sister, Barbara Gayle (Dennis) Kolkhorst, recalls him sprawled on the floor as a preschooler, joyfully counting and writing out numbers into the thousands on the back of old wallpaper rolls. He excelled academically, graduating as valedictorian of his class in 1962. In addition to his intellectual pursuits, Keith worked on the family farm, driving tractors, managing heavy irrigation, and exploring the woods-a balance that shaped his character and resilience. He was an avid reader, a curious inventor interested in electronics and air-powered vehicles, and a proud participant in the Texas Interscholastic League, where he consistently placed top three in the state for Number Sense and Slide Rule. Keith's parents made significant sacrifices to ensure both he and his sister had the opportunity to pursue higher learning. Keith earned a Bachelor of Science in Mathematics from Rice University in 1966, and a Ph.D. in 1970, with his doctoral work focused on algebraic K-theory and group theory. He spent a year working with Fields medal winner John Milnor at Princeton's Institute for Advanced Study from 1970 to 1971. He joined Cornell's Department of Mathematics in 1971, became Associate Professor in 1976, Full Professor in 1981, served as the Department's Chair from 1987 to 1993, and retired as Professor Emeritus in 2019. During his tenure at Cornell, Keith prospered, mentored, lectured, theorized, published, and pursued the greater reaches of intellectual ability throughout the remainder of his career, including winning the Humboldt Award in 1987, and being named an inaugural Fellow of the American Mathematical Society in 2013. His academic legacy includes 25 published papers, a graduate textbook, and an enduring influence on the fields of algebraic K-theory and group theory. Keith, a lifelong bibliophile, was a pioneer in transitioning mathematical resources to the digital era. As Executive Editor of Math Reviews (MR) from 1995-2001, he oversaw its shift from print to digital, and later contributed to projects with the AMS, Project Euclid, and AIM, ultimately playing a pivotal role in advancing mathematical libraries, digitization, and the accessibility of mathematical knowledge on a global scale. His various societal memberships, committees, publications, pupils, mentors, fellows, project memberships, sponsoring of libraries and archives, and leadership and advocacy for access to and preservation of mathematics constitute an almost irrationally large number to comprehend. His legacy lives on through these intricate, intertwined, and ever-converging areas. Keith is survived by his partner and colleague, Michelle "Mikki" Klinger, his children Erick (Cristina), Robin, Lydia (Kris), and Susan (Justin), and his beloved grandchildren Emma, Richard, Lucia, Nerea, Orion, and Haley. He is also survived by his sister, Barbara Gayle Kolkhorst (Harry), of Texas, her children Meason Kolkhorst (Regina) and Charissa Hawryluk (Myron), and her grandchildren Tatum Moore, Michael Hawryluk, and Mandryk Hawryluk. He is also survived by his former wife, Perry Elizabeth Onderdonk, mother of his four children, to whom he was married from 1968 to 1987. Following services in Ithaca, on December 15, 2024, Keith will be buried in Quanah, TX. In lieu of flowers, donations may be made to the Cornell Math Library Endowment at the AMS. Link to the Dennis Fund reference on the AMS Website: https://www.ams.org/giving/ways-to-give/named-endowed-funds Link to make a gift: http://bit.ly/4fo6nXD To send flowers to the family or plant a tree in memory of R. Keith Dennis, please visit our floral store.