Siegfried Johannes Gottwald, born in 1943 in Limbach/Sa., teaches 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) at Leipzig University 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 mid 1960s as he had started his PhD work. His main research topics include the fundamentals of fuzzy set theory, many-valued logic and their relationship 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 of mathematics, as well as in foundational and philosophical 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 of the University of California, Irvine, and in 1991 and again in 1998 at the Department of Philosophy of Indiana University, Bloomington/In.
Actually he is Area Editor for "Non-classical logics and fuzzy set theory" of the leading international journal Fuzzy Sets and Systems. He is member of the Editorial Boards of the journals Information Sciences, Multiple-Valued Logic and Soft Computing as well as of the International Journal of Mathematics and Mathematical Sciences, and he belongs to the Consulting Board of Former Editors of Studia Logica. He is also Correspondant étranger of the series BUSEFAL, and a permanent member of the Program Committee of the Linz Seminar on Fuzzy Set Theory.
He is a member of ASL, EUSFLAT, DMV, DVMLG, and of the Polish Association of Logic and Philosophy of Science.
In 1992 he was honoured with the Research Award „Technische Kommunikation" of the (german) Alcatel-SEL-Foundation (now the Alcatel-Lucent-Foundation). In 2009 he became an IFSA-Fellow, and in 2012 „Distinguished Reviewer of Zentralblatt MATH".
He is married, has three children and enjoys four grandchildren.