A Note On Syntactic Characterization of Incomplete Information in ATEL
Thomas Ågotnes · 2004
It has been argued that the class of semantic structures of Alternating-time Temporal Epistemic Logic (ATEL) are too general and should be restricted in order to properly integrate the semantics of epistemic logic and Alternating-time Temporal Logic (ATL). One of the semantic restrictions is that an agent should have the same choices, or actions, available in indiscernible states. van der Hoek and Wooldridge [10] present a syntactic property claimed to be given by the semantic restriction. This paper points out that the claim does not hold; the semantic restriction is in fact neither sufficient nor necessary for the suggested syntactic property. Furthermore, the difficulty of expressing such local properties of agents seems to be due to a fundamental limit of the expressiveness of ATEL. A redefinition of the ATEL semantics in order to be able to express such properties is briefly discussed.