 The gist of the problem can be illustrated with a simple example. Consider a language with three atomic sentences, \(p, q\), and \(r\), and an information state consisting of three worlds, \(w_{pq}, w_{qr}\), and \(w_{pr}\), where the subscripts of each world indicate which atomic sentences are true at that world. Note that in this information state none of the atomic sentences is known to hold. Now consider an issue which is resolved just in case at least one of the atomic sentences is established, i.e., just in case we know that the actual world is located within one of the ovals depicted in figure 1.