Defining a Double Team Semantics for Generalized Quantifiers

In this brief technical report we sketch a semantics for fi rst-order logic with generalized quantifiers based on double teams. We also define the notion of a generalized atom. Such atoms can be used in order to define extensions of first-order logic with a team-based semantics. We then briefly discuss how our double team semantics relates to game semantics based approaches to extensions of first-order logic with generalized quantifiers

Defining a Double Team Semantics for Generalized Quantifiers

In this brief technical report we sketch a semantics for fi rst-order logic with generalized quantifiers based on double teams. We also define the notion of a generalized atom. Such atoms can be used in order to define extensions of first-order logic with a team-based semantics. We then briefly discuss how our double team semantics relates to game semantics based approaches to extensions of first-order logic with generalized quantifiers

Defining a Double Team Semantics for Generalized Quantifiers (Extended Version)

In this brief technical report we sketch a semantics for first-order logic with generalized quantifi ers based on double teams. We also defi ne the notion of a generalized atom. Such atoms can be used in order to defi ne extensions of first-order logic with a team-based semantics. We then briefly discuss how our double team semantics relates to game semantics based approaches to extensions of fi rst-order logic with generalized quantifi ers

Team Semantics and Recursive Enumerability

It is well known that dependence logic captures the complexity class NP, and it has recently been shown that inclusion logic captures P on ordered models. These results demonstrate that team semantics offers interesting new possibilities for descriptive complexity theory. In order to properly understand the connection between team semantics and descriptive complexity, we introduce an extension D* of dependence logic that can define exactly all recursively enumerable classes of finite models. Thus D* provides an approach to computation alternative to Turing machines. The essential novel feature in D* is an operator that can extend the domain of the considered model by a finite number of fresh elements. Due to the close relationship between generalized quantifiers and oracles, we also investigate generalized quantifiers in team semantics. We show that monotone quantifiers of type (1) can be canonically eliminated from quantifier extensions of first-order logic by introducing corresponding generalized dependence atoms

Some Turing-Complete Extensions of First-Order Logic

We introduce a natural Turing-complete extension of first-order logic FO. The extension adds two novel features to FO. The first one of these is the capacity to add new points to models and new tuples to relations. The second one is the possibility of recursive looping when a formula is evaluated using a semantic game. We first define a game-theoretic semantics for the logic and then prove that the expressive power of the logic corresponds in a canonical way to the recognition capacity of Turing machines. Finally, we show how to incorporate generalized quantifiers into the logic and argue for a highly natural connection between oracles and generalized quantifiers.Comment: In Proceedings GandALF 2014, arXiv:1408.556

Decidability of predicate logics with team semantics

We study the complexity of predicate logics based on team semantics. We show that the satisfiability problems of two-variable independence logic and inclusion logic are both NEXPTIME-complete. Furthermore, we show that the validity problem of two-variable dependence logic is undecidable, thereby solving an open problem from the team semantics literature. We also briefly analyse the complexity of the Bernays-Sch\"onfinkel-Ramsey prefix classes of dependence logic.Comment: Extended version of a MFCS 2016 article. Changes on the earlier arXiv version: title changed, added the result on validity of two-variable dependence logic, restructurin