Lütfi Zadə

Early life and career

Zadeh was born in Baku, Azerbaijan SSR, as Lotfi Aliaskerzadeh, to Rahim Aleskerzade, an Iranian Azerbaijani journalist from Ardabil on assignment from Iran, and Fanya Korenman, a Russian Jewish pediatrician from Odessa and an Iranian citizen. The Soviet government at this time courted foreign correspondents, and the family lived well while in Baku. Zadeh attended elementary school for three years there, which he said “had a significant and long-lasting influence on my thinking and my way of looking at things.”

In 1931, when Zadeh was ten years old, his family moved to Tehran in Iran, his father’s homeland. Zadeh was enrolled in Alborz College, which was a Presbyterian missionary school, where he was educated for the next eight years, and where he met his future wife, Fay. Zadeh says that he was “deeply influenced” by the “extremely decent, fine, honest and helpful” missionaries from the United States who ran the college. “To me they represented the best that you could find in the United States – people from the Midwest with strong roots. They were really ‘Good Samaritans’ – willing to give of themselves for the benefit of others. So this kind of attitude influenced me deeply. It also instilled in me a deep desire to live in the United States.” During this time, Zadeh was awarded several patents.

Despite being more fluent in Russian than in Persian, Zadeh sat for the national university exams and placed third in the entire country. As a student, he ranked first in his class in his first two years. In 1942, he graduated from the University of Tehran with a degree in electrical engineering, one of only three students in that field to graduate that year, due to the turmoil created by World War II, when the United States, Britain and the Soviet Union invaded Iran. Over 30,000 American soldiers were based there, and Zadeh worked with his father, who did business with them as a contractor for hardware and building materials.

In 1943, Zadeh decided to emigrate to the United States, and traveled to Philadelphia by way of Cairo after months of delay waiting for the proper papers or for the right ship to appear. He arrived in mid-1944, and entered the Massachusetts Institute of Technology (MIT) as a graduate student later that year. While in the United States, he changed his name to Lotfi Aliasker Zadeh.

He received an MS degree in electrical engineering from MIT in 1946, and then applied to Columbia University, as his parents had settled in New York City. Columbia admitted him as a doctoral student, and offered him an instructorship as well. He received his Ph.D. in electrical engineering from Columbia in 1949, and became an assistant professor the next year.

Zadeh taught for ten years at Columbia, was promoted to Full Professor in 1957, and taught at the University of California, Berkeley from 1959 on. He published his seminal work on fuzzy sets in 1965, in which he detailed the mathematics of fuzzy set theory. In 1973 he proposed his theory of fuzzy logic.

Personal life and beliefs

Zadeh was called “quick to shrug off nationalism, insisting there are much deeper issues in life”, and was quoted as saying in an interview: “The question really isn’t whether I’m American, Russian, Iranian, Azerbaijani, or anything else. I’ve been shaped by all these people and cultures and I feel quite comfortable among all of them.” He noted in the same interview: “Obstinacy and tenacity. Not being afraid to get embroiled in controversy. That’s very much a Turkish tradition. That’s part of my character, too. I can be very stubborn. That’s probably been beneficial for the development of Fuzzy Logic.”

Zadeh was married to Fay Zadeh and had two children, Stella Zadeh and Norman Zada.

Zadeh died in his home in Berkeley, California, on September 6, 2017, at the age of 96. He is buried in the first Alley of Honor in Baku, Azerbaijan, the city in which he was born. His funeral was well attended by “highly respected people”, including the President of Azerbaijan, Ilham Aliyev.


According to Google Scholar, as of February 2021, Zadeh’s work has been cited about 270,000 times in scholarly works, with the 1965 Fuzzy sets paper receiving more than 115,000 citations.

Fuzzy sets and systems

Zadeh, in his theory of fuzzy sets, proposed using a membership function (with a range covering the interval [0,1]) operating on the domain of all possible values. He proposed new operations for the calculus of logic and showed that fuzzy logic was a generalization of classical and Boolean logic. He also proposed fuzzy numbers as a special case of fuzzy sets, as well as the corresponding rules for consistent mathematical operations (fuzzy arithmetic).

Awards and honors

Zadeh was a Fellow of the Institute of Electrical and Electronics Engineers, the American Academy of Arts and Sciences, the Association for Computing Machinery, the Association for the Advancement of Artificial Intelligence and the International Fuzzy Systems Association, and a member of the National Academy of Engineering. He was also a member of the Academies of Science of Azerbaijan, Bulgaria, Finland, Korea and Poland, and of the International Academy of Systems Studies in Moscow. He received 24 honorary doctorates.

Awards received by Zadeh include, among many others: