Mathematical logic, set theory, lattices and universal algebra form an interconnected framework that underpins much of modern mathematics. At its heart, mathematical logic provides rigorous formal ...

We discuss the work of Paul Bernays in set theory, mainly his axiomatization and his use of classes but also his higher-order reflection principles. Journal Information The Bulletin of Symbolic Logic ...

Then in the early 20th century, Jan Lukasiewicz proposed a three-valued logic (true, possible, false), which never gained wide acceptance. In 1965, Lotfi A. Zadeh of the University of California at ...