AbstractIn this paper, we propose class ADF of data flow schemata, whose expressive power is equivalent to that of class EF of effective functional s. We consider those classes of functionals that can be implemented by schemata of a class as the expressive power of the clas s. In this sense, EF has the most expressive power among the classes of program schemata known to date.In ADF schemata, we use arbitors of data tokens and recursive procedures which are expanded as macro s. We assume that each arc holds at most one token at the same tim e. In the process of verifying the equivalence of ADF and EF, we show that Turing machines can be emulated by ADF schemata.