 Another influential attempt to formalize Karttunen’s generalization with respect to presupposition projection, is the dynamic account of Heim (1983), further developed in Beaver (2001). In a dynamic semantics, the interpretation of sentences is given in terms of their context change potentials rather than their truth conditions (see the entry on  dynamic semantics).  A context (or information state) \(c\) is defined as a set of possible worlds, the worlds compatible with the information available to the conversationalists, along the lines of Stalnaker’s (1978) notion of a context set. The meaning of an atomic sentence \(p\) is identified with its potential to update the input context \(c\), i.e., its potential to eliminate all non-\(p\) worlds from \(c\): \(c[p]=\{w \in c \mid w(p) =1\}\). Here is the dynamic clause for disjunction.