Connecting Logics of Choice and Change

ing from the temporal component that could come from any existing framework, the heart of STIT-style choice is a very simple S5 logic. A STIT choice scenario for a set of agents A is a tuple M = 〈W, {∼i}i∈A, V 〉, where W is a nonempty set, for each i ∈ A, ∼i is an equivalence relation on W (we write [w]i for the equivalence class of w under ∼i) and V is a valuation function. We focus on two agents (A = {1, 2}) for convenience in what follows. STIT choice scenarios are standard multi-agent S5 models, and so a simple modal language describes them: for each i ∈ A,