Walter Rudin
Walter Rudin, a preeminent mathematician and UW-Madison professor, died at age 89 on Thursday, May 20. Yvonne Nagel photo

Walter Rudin, a preeminent mathematician who taught at UW-Madison for 32 years, died Thursday at the age of 89 after suffering from Parkinson’s disease.

Rudin’s advanced work on mathematical analysis may have been of interest to only a small worldwide audience, but his three textbooks were translated into multiple languages and used by generations of college students.

“Especially because of his textbooks, he was known universally among undergraduates and graduates studying mathematics,” said Alexander Nagel, a colleague in the UW-Madison math department.

Rudin was born in Vienna, Austria, on May 2, 1921, to a prosperous Jewish family. His family fled Austria in 1938 after the country was annexed to the Nazis. He served in the British Army and Navy during WWII, coming to the United States in late 1945. He got a doctorate in math from Duke University in 1949 and joined the UW-Madison math department in 1959.

After retiring in 1991, Rudin wrote about his early life, turbulent war years and math career in an autobiography titled “As I Remember It.”

But thousands of students are likely more familiar with Rudin’s writings from his “Principles of Mathematical Analysis,” published in 1953 and often used in junior and senior level college calculus courses. It is playfully called “Baby Rudin” by students and the math community, Nagel said, to differentiate it from his second book, “Real and Complex Analysis,” which is called “Big Rudin.”

Rudin published a third textbook, “Functional Analysis,” in 1973 and won the Leroy P. Steele Prize from the American Mathematical Society for writing in 1993.

Rudin is survived by his wife, Mary Ellen, who was also a professor in the math department, four children and four grandchildren.

Because he served as a mentor to so many doctoral students, his work is carried on through many “mathematical children, grandchildren and great-grandchildren,” Mary Ellen Rudin said.