More formally, according to <cite>Rudolph and Giesbrecht (2010)</cite> , the underlying idea can be described as follows: "Given a mapping · : Σ → S from a set of tokens in Σ into some semantical space S, the composition operation is defined by mapping sequences of meanings to meanings: : S → S. So, the meaning of the sequence of tokens σ 1 · · · σ n can be obtained by first applying the function · to each token and then to the sequence σ 1 · · · σ n , as shown in Figure 2 ".