 The central idea is that question meanings are pairs \(\langle B,R\rangle\), where \(B\) is called the background and \(R\) the restriction. \(B\) is a function that, when applied to the semantic value of an appropriate term answer to the question, yields a proposition. \(R\) specifies what appropriate term answers are, i.e., what the semantic entities are that \(B\) can be applied to.