Complexity and definability issues in L Pi 1/2
In this work we investigate several complexity and definability problems for the logic L Pi 1/2. 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 L Pi 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 L Pi 1/2.
real closed fields fuzzy logics left-continuous t-norms decidability