A Distributed Agent-based Approach for Supporting Group Formation in P2P e-Learning Fabrizio Messina and Giuseppe Pappalardo and Domenico Rosaci and Corrado Santoro and Giuseppe M.L. Sarn´ e Abstract Peer-to-Peer (P2P) e-Learning systems have been designed to support people, providing them with the advantages brought by the Internet technology.They can be be effectively used to implement cooperative e-Learning systems, where the available knowledge for a student is not only from teachers, but also from other students having similar interests and preference. In such a scenario, a central issue is that of supporting the formation of groups of users having similar interests and satisfying personal users’ constraints. In this paper we propose a novel approach, called HADEL (Hyperspace Agent-based E-Learning), based on an overlay network of software agents. Our approach preserves the users’ privacy, allowing to locally maintain sensitive user’s data and inferring the properties necessary for determining the groups by using agents acting as personal assistants. The results obtained by some tests performed on simulated e-Learning environments show the efficiency of our approach, that suitably exploits the topology of the overlay network, which exhibits the small-world properties. 1 Introduction Nowadays, due to the rapid development of information technology, important changes have been produced in the fundamental ways that people acquire and dis- seminate knowledge. Several e-Learning systems have been designed to support people, providing them with the advantages brought by the Internet technology. In particular, the Peer to Peer (P2P) paradigm has been widely recognized as the key Fabrizio Messina, Giuseppe Pappalardo, Corrado Santoro Dipartimento di Matematica e Informatica, Universit` a di Catania, V.le Andrea Doria 6, 95125 Catania, Italy, e-mail: {fmessina,pappalardo,santoro}@dmi.unict.it Domenico Rosaci, Giuseppe M.L. Sarn´ e {DIIES, DICEAM}, University “Mediterranea” of Reggio Calabria, Via Graziella, Feo di Vito 89122 Reggio Calabria (RC), Italy, e-mail: {domenico.rosaci,sarne}@unirc.it 1 This is the authors' version of the paper. The final publication is available at Springer via DOI: 10.1007/978-3-319-03524-6_27