DECIDING WHETHER A RELATION DEFINED IN PRESBURGER LOGIC CAN BE DEFINED IN WEAKER LOGICS

摘要

We consider logics on Z and N which are weaker than Presburger arithmetic and we settle the following decision problem: given a fe-ary relation on Z and N which are first order definable in Presburger arithmetic, are they definable in these weaker logics? These logics, intuitively, are obtained by considering modulo and threshold counting predicates for differences of two variables.