Complexity and definability issues in Łπ1/2

Abstract

In this work we investigate several complexity and definability problems for the logic łπ1/2. We show that the universal fragment of the theory of real closed fields can be faithfully interpreted in such a logic. Then we investigate the logics of t-norms definable in Łπ 1/2, and we prove that they are all in PSPACE. Finally we show that the most important fuzzy logics are complete with respect to classes of t-norms which are definable in łπ1/2. © the Author, 2007.