Multi Valued Logics: A Review

The present work, starting from the fuzzy sets theory introduced by Zadeh in 1965, reviews its generalizations and other relevant theories developed during the last 50 years. Those theories gave genesis to multi-valued logics, which help to treat better the uncertain or vague situations that frequently appear in problems of every day life, science and technology. Therefore they need not be seen as competitive, but as complementary to the traditional bi-valued logic of Aristotle. The article offers the basic framework to those wanting to study further the multi-valued logics that have found recently many and important applications to almost all sectors of the human activity.