Ruth Bari

Ruth Aaronson Bari (November 17, 1917 – August 25, 2005) was an American mathematician known for her work in graph theory and algebraic homomorphisms. The daughter of Polish-Jewish immigrants to the United States, she was a professor at George Washington University beginning in 1966. She was the mother of environmental activist Judi Bari, science reporter Gina Kolata and art historian Martha Bari.


Bari grew up in Brooklyn and attended Brooklyn College, earning her bachelor's degree in mathematics in 1939. She earned her MA at Johns Hopkins University in 1943, but had originally enrolled in the doctoral program. When the university suggested that women in the graduate program should give up their fellowships so that men returning from World War II could study, Bari acceded.[1] After marrying Arthur Bari she spent the next two decades devoted to family. She returned to Johns Hopkins, where she completed her dissertation on "absolute reducibility of maps of at most 19 regions" in 1966 at the age of 47.

Bari’s dissertation explored chromatic polynomials and the Birkhoff-Lewis conjecture. She determined that “Because of the fact that all other cubic maps with fewer than 20 regions contain at least one absolutely reducible configuration, it follows that the Birkhoff-Lewis conjecture holds for all maps with fewer than 20 regions.”[2] Her Ph.D. advisor was Daniel Lewis, Jr.[3] After receiving her degree, mathematician William Tutte invited Bari to spend two weeks lecturing on her work in Canada at the University of Waterloo. Bari's work in the areas of graph theory and homomorphisms—and especially that of chromatic polynomials—has been recognized as influential. In 1976, two professors relied on computer work to solve the perennial problem of Bari’s dissertation, involving the four-color conjecture. When her daughter Martha asked her if she felt cheated by the technological solution, Bari replied, “I’m just grateful that it was solved within my lifetime and that I had the privilege to witness it.”[1]

During her teaching career, Bari participated in a class-action lawsuit against George Washington University, which protested inequalities in promotion and pay for female faculty members. The protests were successful, and Bari retired at the legally mandated age of 70 in 1988 with the distinction of professor emeritus.

Community and Family Life

Bari was active in the Washington, DC community. In the early 1970s, Bari used a grant from the National Science Foundation to start a master's degree program in teaching mathematics. She felt that math teachers in DC public schools were not as well prepared as they needed to be.[4]

Her daughters also became influential in their fields. Gina Kolata is a mathematics, health and science journalist for the New York Times. Judi Bari (1949 – 1997) was a leading labor and environmental activist and feminist, who survived an assassination attempt. Dr. Martha Bari is an art historian at Hood College

Bari died on August 25, 2005. She was survived by her husband of 64 years of marriage, Arthur (1913-2006). Besides their three daughters, they had two grandchildren each by both Judi and Gina. She had lived in Silver Spring, Maryland since 1963 and was 87 years old at the time of her death.[4]


  1. ^ a b Kolata
  2. ^ Bari, Ruth. Abstract: “Absolute Reducibility of Maps of at Most 19 Regions.” Biographies of Women Mathematicians
  3. ^ Mathematics Genealogy Project
  4. ^ a b Washington Post