Automated Purchase Negotiations in a Dynamic Electronic Marketplace ⋆ Miguel A. López-Carmona, Juan R. Velasco, Bernardo Alarcos Department of Automática, University of Alcalá Edificio Politécnico, Ctra. NII, km. 33.600 28871 Alcalá de Henares (Madrid), Spain Phone: +34 918856673, Fax:+34 918856641 {miguellop,juanra,bernardo}@aut.uah.es Abstract. Nowadays, there is a surge of B2C and B2B e-commerce op- erated on the Internet. However, many of these systems are often nothing more than electronic product or service catalogues. Against this back- ground, it is argued that new generation systems based on automatic negotiation will emerge. This paper covers a particular kind of auto- matic negotiation systems, where a number of participants in a mobile dynamic electronic marketplace automatically negotiate the purchase of products or services, by means of multiple automated one-to-one bar- gainings. In a dynamic e-marketplace, the number of buyers and sellers and their preferences may change over time. By mobile we mean that buyers in a commercial area may initiate simultaneous negotiations with several sellers using portable devices like cell phones, laptops or personal digital assistants, so these negotiations do not require participants to be colocated in space. We will show how an expressive approach to fuzzy constraint based agent purchase negotiations in competitive trading en- vironments, is ideally suited to work on these kind of e-marketplaces. An example of mobile e-marketplace, and a comparison between an expres- sive and an inexpressive approach will be presented to show the efficiency of the proposed solution. 1 Introduction In the commercial and service surroundings of a city situations occur in which people need certain information or service. For example, a person who needs information on a certain product and is interested in looking for the best price. It requires to go to the commerce and to ask the price, having sometimes to wait for tails. Another example is when a tourist looks for a restaurant to have lunch in a zone in which a great number of restaurants is concentrated, so the tourist has to walk (sometimes for a long time) and observe the menus and the prices. The city councils and retailers of the cities can deploy a platform of services based on wireless technology, and with a low cost give a gratuitous service to the users, solving the described problems. A user who has a Personal Digital ⋆ This work has been supported by the UAH grant PI2005/082.