Siegfried Johannes Gottwald taught at Leipzig University mathematics and logic since 1972, the year he got his “facultas docendi” for the field of mathematics. He has studied mathematics at this university from 1961 to 1966, got his PhD in mathematics there in 1969, and his Habilitation degree in 1977, also in mathematics. He became Lecturer in Logic (Hochschuldozent) there in 1979, and Associate (=ausserordentlicher) Professor in 1987. From 1992 up to his retirement in 2008 he was Full Professor for “Nonclassical and Mathematical Logic” at Leipzig University.
He has been active in research on fuzzy sets and fuzzy methodologies since the late 1960s. His main topics include the fundamentals of fuzzy set theory, many-valued logic and their relation to fuzzy sets, fuzzy relation equations and their relationship to fuzzy control, as well as fuzzy logic and approximate reasoning. He is also interested in the history of logic and mathematics, as well as in philosophical and foundational issues for mathematics and computer science.
He has published several books on many-valued logic, fuzzy sets and their applications, was coauthor of a textbook on calculus and of a reader in the history of logic, and coedited and coauthored a biographical dictionary of mathematicians.
He was a visiting scholar at Warsaw University/Polish Academy of Sciences in 1972 and 1973, at the Department of Computer Science of the TH Darmstadt in 1992, in 1991 at the Department of Philosophy at University of California, Irvine, and in 1991 and again in 1998 at the Department of Philosophy at Indiana University, Bloomington/In.
He was a member of ASL, EUSFLAT, DMV, and DVMLG. In 1992 he was honoured with the Research Award “Technische Kommunikation” of the then Alcatel-SEL-Foundation, now Alcatel-Lucent-Foundation. In 2009 he became “Fellow” of the International Fuzzy Systems Association (IFSA). And from 2012 to 2015 he was “Distinguished Reviewer of Zentralblatt MATH”.
He was Area Editors for Logic of the leading international journal Fuzzy Sets and Systems. He belonged to the editorial boards of further journals. And he was a permanent member of the Program Committee of the Linz Seminar on Fuzzy Set Theory.
Nichtklassische und mathematische Logik
Mehrwertige und Fuzzy-Logiken
Unscharfe Mengen, Fuzzy-Relationen und Anwendungen
Geschichte der Mathematik und Logik