Lotfi Zadeh, a former UC Berkeley professor and the architect of the theory of “fuzzy logic,” a precursor to artificial intelligence, died last week at the age of 96.

Zadeh, who was born in Azerbaijan in 1921, was a pioneer in the fields of electrical engineering and applied mathematics. He is known for publishing his 1965 paper “Fuzzy sets,” which introduced a new theory called “fuzzy logic.” Fuzzy logic was an early breakthrough in the development of artificial intelligence — this paved the way for further development in machine learning, which is used in everything from self-driving cars to rice cookers.

His theory developed a bridge between discrete binary systems and continuums, which more accurately reflects human behavior. The theory, which earned him both respect and criticism in the mathematical world, has been cited over 90,000 times.

Norman Zada, Lotfi Zadeh’s son, said his father was a “driven person” whose work made up 90 percent of his identity. He was still attending conferences three months prior to his death. Norman said his father was very supportive of his doctoral students, always prioritizing their success.

Norman said his father was extremely committed to his work, which was reflected in his methodical and composed nature.

“He was never satisfied,” Zada said.

Zada recalled the time when his father asked Zada to edit and give feedback to his infamous “Fuzzy sets” paper. For Zadeh, work was life.

“Some people just like to sit back with a Bud Light,” Zada said. “I don’t think he ever had Bud Light.”

According to his son, outside of work, Zadeh was an avid tennis player, dancer and photographer. He also managed to take pictures of three U.S. presidents, namely Harry Truman, Richard Nixon and Dwight Eisenhower.

Zadeh, who served as chair of UC Berkeley’s department of electrical engineering from 1963 to 1968, played a pivotal role in unifying the disciplines of electrical engineering and computer science to create EECS — a combination that was then applied by other universities such as MIT.

“(He) was a prime mover in the name change which became a huge force nationwide,” said Elwyn Berlekamp, campus professor emeritus of EECS and mathematics.

Zadeh’s career, however, was not devoid of criticism, which gave him grief at times. Zada attributes some people’s “less than loving” behavior towards his father to jealousy. Fortunately for Zadeh, he knew how to change a negative into a positive.

Zada recalled an incident where someone stood up in Soda Hall to criticize Zadeh, to which the late professor replied: “Thank you for your interest in my work.”

Zadeh’s legacy transcends that of his far-reaching contributions to the fields of electrical engineering, mathematics and computer science. Those who knew him highlighted his undying enthusiasm, helpfulness and general gregariousness.

“He was really quite a colorful character,” said S. Shankar Sastry, dean of the College of Engineering at UC Berkeley. “He and his wife would adopt untold numbers of visitors and grad students and invite them to their home and shower them with hospitality. He really wanted to make Berkeley a home for people that came from faraway places.”

Zada said he has received an outpouring of love and support from people in the United States and Azerbaijan, including the Azerbaijani president. According to Zada, more than 200 highly respected people in Azerbaijan attended Zadeh’s funeral.