Toward model theory with data values

Abstract

We define a variant of first-order logic that deals with data words, data trees, data graphs etc. The definition of the logic is based on Fraenkel-Mostowski sets (FM sets, also known as nominal sets). The key idea is that we allow infinite disjunction (and conjunction), as long as the set of disjuncts (conjunct) is finite modulo renaming of data values. We study model theory for this logic; in particular we prove that the infinite disjunction can be eliminated from formulas. © 2012 Springer-Verlag Berlin Heidelberg.