Joseph Halpern, an Israeli-born American computer scientist and professor at Cornell University, died on February 13, 2026, at age 72.
Born in Israel in 1953, he studied mathematics at the University of Toronto, earning a B.S. in 1975, and later received a Ph.D.
in mathematics from Harvard University in 1981. His research focused on reasoning about knowledge and uncertainty. Halpern wrote three books, including Actual Causality, Reasoning about Uncertainty and Reasoning About Knowledge. He won the 1997 Gödel Prize and the 2009 Dijkstra Prize, and in 1993 he was elected a Fellow of the Association for the Advancement of Artificial Intelligence.
Joseph Yehuda Halpern (May 29, 1953 – February 13, 2026) was an Israeli-American professor of computer science at Cornell University. Most of his research is on reasoning about knowledge and uncertainty.