In recent years, due to the increasing popularization of data broadcasting, the volume and variety of data being broadcast are rapidly increasing. In this environment, as it is dicult for users to search for information from a large amount of broadcast data, there is an increasing demand for ltering techniques that automatically extract only the necessary data. Consequently, a number of ltering methods have been proposed. However, mathematical representation of these methods does not exist. Thus, it is not possible to qualitatively evaluate various ltering methods, optimize processing methods in ltering, or design a declarative language for ltering processes. In this paper, we dene ltering as a function, and express the properties of ltering methods by the constraints satised by this function. By showing the inclusion relation of constraints representing the properties of ltering, we clarify the relationship between the properties of ltering. Using the framework proposed i...