Lotfi A. Zadeh

Lotfi Aliasker Zadeh[5] (/ˈzɑːd/; Azerbaijani: Lütfəli Rəhim oğlu Ələsgərzadə;[6] Persian: لطفی علی‌عسگرزاده;[4] February 4, 1921 September 6, 2017)[1][2] was a mathematician, computer scientist, electrical engineer, artificial intelligence researcher and professor emeritus[7] of computer science at the University of California, Berkeley.

Lotfi A. Zadeh
(5 November 2005)
Lotfi Aliasker Zadeh

(1921-02-04)February 4, 1921
DiedSeptember 6, 2017(2017-09-06) (aged 96)[1][2]
Alma materUniversity of Tehran
Columbia University
Known forFounder of fuzzy mathematics,
fuzzy set theory, and fuzzy logic, Z numbers, Z-transform
AwardsEringen Medal (1976)
IEEE Hamming Medal (1992)
Rufus Oldenburger Medal (1993)
IEEE Medal of Honor (1995)
2012 BBVA Foundation Frontiers of Knowledge Award
Honorary Doctorate of Tehran University (2016)[4]
ACM Fellow
IEEE Fellow
AAAS Fellow
AAAI Fellow
Member of the National Academy of Engineering
Founding Member of Eurasian Academy
Scientific career
FieldsMath, Electrical Engineering, AI
ThesisFrequency analysis of variable networks (1949)
Doctoral advisorJohn R. Ragazzini
Doctoral studentsJoseph Goguen

Zadeh was best known for proposing fuzzy mathematics consisting of these fuzzy-related concepts: fuzzy sets,[8] fuzzy logic,[9] fuzzy algorithms,[10] fuzzy semantics,[11] fuzzy languages,[12] fuzzy control,[13] fuzzy systems,[14] fuzzy probabilities,[15] fuzzy events,[15] and fuzzy information.[16]

Zadeh was a founding member of the Eurasian Academy.[17]

Life and career

Zadeh was born in Baku, Azerbaijan Soviet Socialist Republic,[18] as Lotfi Aliaskerzadeh,[19] to an Iranian Azerbaijani father from Ardabil, Rahim Aleskerzade, who was a journalist on assignment from Iran, and a Russian Jewish mother, also an Iranian citizen,[20][21] Fanya Korenman, who was a pediatrician from Odessa.[22][23] The Soviet government at this time courted foreign correspondents, and the family lived well while in Baku.[24] Zadeh attended elementary school for three years there,[24] which he said "had a significant and long-lasting influence on my thinking and my way of looking at things."[25]

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.[24] 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."[25] During this time, Zadeh was awarded several patents.[24]

Despite being more fluent in Russian than in Persian, Zadeh sat for the national university exams and placed third in the entire country.[24] 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, whose ruler, Reza Shah, was pro-German. 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.[26]

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.[26] While in the United States, he changed his name to Lotfi Asker Zadeh.[19]

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.[26] Columbia admitted him as a doctoral student, and offered him an instructorship as well.[26] He received his Ph.D. in electrical engineering from Columbia in 1949, and became an assistant professor the next year.[23][26]

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."[27] 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."[28] He described himself as "an American, mathematically oriented, electrical engineer of Iranian descent, born in Russia."[23]

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

Zadeh died in his home in Berkeley, California,[3] on September 6, 2017, at the age of 96.[1][2] He is buried in the first Alley of Honor in Baku, Azerbaijan, where he was born.[3] His funeral was well attended by "highly respected people", including the president of Azerbaijan.[29] A month previous to his death, the University of Tehran had released an erroneous report that Zadeh had died, but withdrew it several days later.[30]


According to Google Scholar, as of October 2019, Zadeh's work has been cited about 230,000 times in scholarly works, with the 1965 "Fuzzy Sets" paper receiving more than 100,000 citations.[31]

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 generalisation 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).[32]

Other contributions

Zadeh is also credited, along with John R. Ragazzini, in 1952, with having pioneered the development of the z-transform method in discrete time signal processing and analysis. These methods are now standard in digital signal processing, digital control, and other discrete-time systems used in industry and research. He was an editor of the International Journal of Computational Cognition.

Zadeh's most recent work included computing with words and perceptions. His recent papers include From Search Engines to Question-Answering Systems—The Role of Fuzzy Logic, Progress in Informatics, No. 1, 1–3, 2005; and Toward a Generalized Theory of Uncertainty (GTU)—An Outline, Information Sciences, Elsevier, Vol. 172, 1–40, 2005.

Selected publications

  • 1965. "Fuzzy sets". Information and Control. 1965; 8: 338–353.
  • 1965. "Fuzzy sets and systems". In: Fox J, editor. System Theory. Brooklyn, NY: Polytechnic Press, 1965: 29–39.
  • 1972. "A fuzzy-set-theoretical interpretation of linguistic hedges". Journal of Cybernetics 1972; 2: 4–34.
  • 1973. "Outline of a new approach to the analysis of complex systems and decision processes". IEEE Trans. Systems, Man and Cybernetics, 1973; 3: 28–44.
  • 1974. "Fuzzy logic and its application to approximate reasoning". In: Information Processing 74, Proc. IFIP Congr. 1974 (3), pp. 591–594.
  • 1975. "Fuzzy logic and approximate reasoning". Synthese, 1975; 30: 407–428.
  • 1975. "Calculus of fuzzy restrictions". In: Zadeh LA, Fu KS, Tanaka K, Shimura M, editors. Fuzzy Sets and their Applications to Cognitive and Decision Processes. New York: Academic Press, 1975: 1–39.
  • 1975. "The concept of a linguistic variable and its application to approximate reasoning", I-III, Information Sciences 8 (1975) 199–251, 301–357; 9 (1976) 43–80.
  • 2002. "From computing with numbers to computing with words — from manipulation of measurements to manipulation of perceptions". International Journal of Applied Math and Computer Science, pp. 307–324, vol. 12, no. 3, 2002.
  • 2012. Computing With Words. Principal Concepts and Ideas. Berlin: Springer, 2012.
A complete list of publications is on the website: https://www2.eecs.berkeley.edu/Pubs/Faculty/zadeh.html

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.[5] 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 has received 24 honorary doctorates.[7]

Awards received by Zadeh include, among many others:

See also



  1. Staff (September 7, 2017) "Lotfi Zadeh has passed away" EECS at UC Berkeley: News
  2. Associated Press (September 8, 2017) "Lotfi Zadeh dead: Computing revolutionary and founder of fuzzy logic dies aged 96" International Business Times
  3. Metz, Cade (September 11, 2017) "Lotfi Zadeh: Father of Mathematical Fuzzy Logic, Dies at 96" The New York Times
  4. "Granting honorary doctorate from Tehran University to professor Lotfizadeh". Official website of University of Tehran (UT) (in Persian). Tehran, Iran. March 9, 2016. Retrieved 1 July 2017.
  5. Dr. Lotfi A. Zadeh was elected in 1973 as a member of National Academy of Engineering in Computer Science & Engineering and Electronics, Communication & Information Systems Engineering.
  6. Diasporla İş üzrə Dövlət Komitəsi
  7. "Lotfi A. Zadeh" faculty page from College of Engineering, Electrical Engineering and Computer Science, University of California at Berkeley
  8. Zadeh, L. A. (1965). "Fuzzy sets". Information and Control. 8 (3): 338–353. doi:10.1016/S0019-9958(65)90241-X.
  9. Zadeh, L. A. (1996). "Fuzzy logic = computing with words". IEEE Transactions on Fuzzy Systems. 4 (2): 103–111. doi:10.1109/91.493904.
  10. Zadeh, L. A. (1968). "Fuzzy algorithms". Information and Control. 12 (2): 94–102. doi:10.1016/S0019-9958(68)90211-8.
  11. Zadeh, L. A. (1971). "Quantitative fuzzy semantics". Information Sciences. 3 (2): 159–176. doi:10.1016/S0020-0255(71)80004-X.
  12. Lee, E. T.; Zadeh, L. A. (1969). "Note on fuzzy languages". Information Sciences. 1 (4): 421–434. doi:10.1016/0020-0255(69)90025-5.
  13. Zadeh, L. A. (1972). "A Rationale for Fuzzy Control". Journal of Dynamic Systems, Measurement, and Control. 94: 3. doi:10.1115/1.3426540.
  14. Zadeh, L. (1969). "Toward a theory of fuzzy systems" (PDF). Retrieved 2014. Check date values in: |accessdate= (help)
  15. Zadeh, L. A. (1984). "Fuzzy probabilities". Information Processing & Management. 20 (3): 363–372. doi:10.1016/0306-4573(84)90067-0.
  16. Zadeh, L. A. (1997). "Toward a theory of fuzzy information granulation and its centrality in human reasoning and fuzzy logic". Fuzzy Sets and Systems. 90 (2): 111–127. doi:10.1016/S0165-0114(97)00077-8.
  17. Eurasian Academy Official Site
  18. At this time, the Azerbaijan SSR was an independent republic, created by the Red Army. It would become part of the Transcaucasian Socialist Federative Soviet Republic in March 1922, and then part of the Soviet Union in December 1922.
  19. McNeil & Freiberger, p.17
  20. Zadeh, Lotfi A (2015-05-21). "Fuzzy logic—a personal perspective". Fuzzy Sets and Systems. 281: 4–20. doi:10.1016/j.fss.2015.05.009.
  21. "Jews in Computer & Information Science" on the JINFO.org website
  22. Анвар Унугви "Жанет Селимова" Archived 2014-07-14 at the Wayback Machine (Mamoirs of Lotfi A. Zadeh's cousin in Baku, theatrical director, professor Zhanet Selimova).
  23. Gale, Thomson. Lotfi Asker Zadeh Biography World of Computer Science
  24. McNeil & Freiberger, p.18
  25. Blair, Betty. Interview with Lotfi Zadeh (December 1999) in "Famous People: Then and Now Lotfi Zadeh, Creator of Fuzzy Logic (1921– )" Azerbaijan International (7.4) (Winter 1999)
  26. McNeil & Freiberger, p.19
  27. Blair, Betty. "Short Biographical Sketch". Azerbaijan International, Vol. 2:4 (Winter 1994), p. 49.
  28. Blair, Betty. "Interview with Lotfi Zadeh, Creator of Fuzzy Logic". Azerbaijan International, Vol. 2:4 (Winter 1994), pp. 46 ff.
  29. Brewer, Jared and Shakeel, Azwar (September 17, 2017) "UC Berkeley professor, creator of ‘fuzzy logic’ Lotfi Zadeh dies at 96" The Daily Californian
  30. Staff (August 12, 2017) "Tehran University withdraws report on death of researcher" Press-TV
  31. Lotfi A. Zadeh profile page on Google Scholar (accessed October 19, 2019).
  32. McNeil & Freiberger, passim
  33. "IEEE James H. Mulligan, Jr. Education Medal Recipients" (PDF). IEEE. Retrieved September 3, 2011.
  34. "IEEE Richard W. Hamming Medal Recipients" (PDF). IEEE. Retrieved May 29, 2011.
  35. "Rufus Oldenburger Medal". American Society of Mechanical Engineers. Retrieved February 12, 2013.
  36. "IEEE Medal of Honor Recipients" (PDF). IEEE. Archived from the original (PDF) on 2015-04-22. Retrieved September 3, 2011.
  37. "Richard E. Bellman Control Heritage Award". American Automatic Control Council. Retrieved February 10, 2013.
  38. "AI's Hall of Fame" (PDF). IEEE Intelligent Systems. 26 (4): 5–15. 2011. doi:10.1109/MIS.2011.64.
  39. "IEEE Computer Society Magazine Honors Artificial Intelligence Leaders". DigitalJournal.com. August 24, 2011. Retrieved September 18, 2011. Press release source: PRWeb (Vocus).
  40. "2017: Fuzzy Logic, Clear Impact". The Golden Goose Award. Retrieved 2019-12-13.


  • McNeil, Daniel and Freiberger, Paul. Fuzzy Logic: The discovery of a revolutionary computer technology – and how it is changing our world. New York: Simon & Schuster, 1993. ISBN 0-671-73843-7

Further reading

  • Fuzzy Sets and Systems. The main journal of the field which contains many contributions by its founder.
  • Seising, Rudolf. The Fuzzification of Systems: The Genesis of Fuzzy Set Theory and Its Initial Applications – Developments up to the 1970s (Studies in Fuzziness and Soft Computing, Vol. 216) Berlin, New York, [et al.]: Springer 2007.
  • Zadeh, Fay. "My Life and Travels with the Father of Fuzzy Logic". 1998, TSI Press, Albuquerque, NM.
  • Zadeh, Lofti A. "Lotfi Visions", two-part interview with Jack J. Woehr, Dr. Dobb's Journal, July, 1994 (part 1) and August, 1994 (part 2).

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