Finite-Degree Predicates and Two-Variable First-Order Logic

Charles Paperman (1)

1 UW - University of Warsaw

We consider two-variable first-order logic on finite words with a fixed number of quantifier alternations. We show that all languages with a neutral letter definable using the order and finite-degree predicates are also definable with the order predicate only. From this result we derive the separation of the alternation hierarchy of two-variable logic on this signature.

Domaines: Logique en informatique [cs.LO]

Charles Paperman. Finite-Degree Predicates and Two-Variable First-Order Logic. 2015. ⟨hal-01178299v2⟩