Local normal forms for logics over traces

Abstract

We investigate local and global paradigms of reasoning about distributed behaviours, modelled as Mazurkiewicz traces, in the context of first-order and monadic second-order logics. We describe new normal forms for properties expressible in these logics. The first normal form, surprisingly, yields a decomposition of a global property as a boolean combination of local properties. The second normal form strengthens McNaughton's theorem and states that global properties of infinite behaviours may also be described as boolean combinations of recurring properties of finite local histories of the behaviours. We briefly touch upon some of the interesting applications of these normal forms.