Dynamic Alternate in NS2

This article proposes a formalism called alternating-time temporal dynamic epistemic logic (ATDEL). It is somewhat similar to the coalition announcement logic (CAL) proposed by Ågotnes et al. As well as CAL, ATDEL has a coalition operator that enables to express sentences like ‘there is an action a for each member of the group of agents G after which ϕ is true, in spite of what the agents outside the group G do’. One of the differences here, is that such actions a can also have factual effects. They are not restricted only to public announcements, as in CAL. In addition, this operator is coupled with temporal operators similar to those in alternating-time temporal logic. For instance, ATDEL has operators enabling to express sentences like ‘the group of agents G is able to enforce that ψ is true until ϕ becomes true’. Comparisons with several other logics, such as public announcement logic with assignment, group announcement logic and arbitrary public announcement logic are drawn. Since the descriptions of actions in ATDEL is concise, it is advocated that one of its main advantages is the possibility to have reasonable-sized multi-agent systems specifications. Moreover, a sound and complete axiomatization, model checking and satisfiability checking algorithms as well as some complexity bounds are provided. Satisfiability checking in ATDEL with finite sets of actions is shown to be decidable.