Logical Methods in Computer Science Volume 15, Issue 3, 2019, pp. 17:1–17:28 Submitted Mar. 07, 2019 https://lmcs.episciences.org/ Published Aug. 20, 2019 ON THE SUCCINCTNESS OF ATOMS OF DEPENDENCY MARTIN LUCK¨ a AND MIIKKA VILANDER b a Leibniz University Hannover e-mail address:
[email protected] b Tampere University e-mail address:
[email protected] Abstract. Propositional team logic is the propositional analog to first-order team logic. Non-classical atoms of dependence, independence, inclusion, exclusion and anonymity can be expressed in it, but for all atoms except dependence only exponential translations are known. In this paper, we systematically compare their succinctness in the existential fragment, where the splitting disjunction only occurs positively, and in full propositional team logic with unrestricted negation. By introducing a variant of the Ehrenfeucht{Fra¨ıss´e game called formula size game into team logic, we obtain exponential lower bounds in the existential fragment for all atoms. In the full fragment, we present polynomial upper bounds also for all atoms. 1. Introduction As a novel extension of classical logic, team semantics provides a framework for reasoning about whole collections of entities at once, as well as their relation with each other. Such a collection of entities is called a team. Originally, team semantics was introduced by Hodges [Hod97] to provide a compositional approach to logic of incomplete information, such as Hintikka's and Sandu's independence-friendly logic (IF-logic) [HS89]. In his seminal work, V¨a¨an¨anen[V¨a07] introduced dependence logic which extends first-order logic by so-called dependence atoms, atomic formulas =(x1; : : : ; xn; y) that in- tuitively express that the value of y depends only on the values of x1; : : : ; xn.