 We now turn our attention to a line of work that aims to capture the semantics of questions in a dynamic framework. The first theories in this line of work were developed by Jäger (1996), Hulstijn (1997), and Groenendijk (1999). Aloni et al. (2007b) contains a collection of papers elaborating on these early proposals. All these theories essentially reformulate the partition theory of questions in the format of an update semantics (Veltman 1996). This means that they explicitly identify meanings with context change potentials, i.e., functions over discourse contexts. However, unlike a simple update semantics where discourse contexts are modeled as sets of worlds—embodying the information established in the discourse so far—these theories provide a more refined model of discourse contexts, one that also embodies the issues that have been raised so far. More specifically, a discourse context is modeled as an equivalence relation \(R\) over a set of worlds \(C\). The set of worlds \(C\), i.e., the domain of \(R\), can be thought of as the context set, i.e., the set of all worlds that are compatible with the information established in the discourse so far. \(R\) itself induces a partition on \(C\), and can thus be taken to encode the issues that have been raised so far. More specifically, we can think of \(R\) as relating two worlds \(w\) and \(v\) just in case the difference between \(w\) and \(v\) is not (yet) at issue, i.e., the discourse participants have not yet expressed an interest in information that would distinguish between \(w\) and \(v\). In other words, \(R\) can be conceived of as a relation encoding indifference (Hulstijn 1997).