Introduction

The KURE package provides functions to manipulate binary relations.

The package provides a large set of operations on relations and graphs, functions to convert homogeneous relations into graphs and vice versa and some operations for reading relations, graphs, relational functions and relational programs from files and for storing relations, graphs and relational functions into files.

The KURE package can be used in two ways:

• As a black box. In this case, the application program that needs to manipulate relations only uses the exported functions of the package. The set of functions included into the KURE package allows many applications to be written in this way. Section 3 describes how to use the exported functions of the package. An application written in terms of the exported functions of the package needs not concern itself with the details of representations and storage of relations.
• As a clear box. When writing a sophisticated application based on relations, efficiency often dictates that some functions be implemented as direct recursive manipulation of the relations, instead of being written in terms of existing primitive functions. Section 4 give a short introduction into the usage of the KURE package as a clear box.

In the following, the reader is supposed to be familiar with the basic ideas about relations, as found, for instance, in [SS93].