adfa, p. 1, 2011. © Springer‐Verlag Berlin Heidelberg 2011 HPSG grammar treating different forms of Arabic coordination Sirine Boukedi 1 and Kais Haddar 2 University of Sfax 1/2 , Faculty of Science Economy and management 1 and Faculty of Sciences 2 MIR@CL laboratory 1/2 sirine.boukedi@gmail.com, Kais.haddar@yahoo.fr Abstract. Researchers working in Natural Language processing (NLP) found many problems, at different levels. The main problem encountered is the treat- ment of complicated phenomena, essentially the coordination. This phenome- non is very important. In fact, it is very frequent in various corpora and has al- ways been a center of interest in NLP. Unfortunately, the few works working on this structure treated only some coordinated forms using constructed parsers which are generally so heavy. In this context, our work aims to develop a Head- driven Phrase Structure grammar (HPSG) representing all the different forms of Arabic coordination, based on a proposed typology. The constructed grammar was validated with Linguistic Knowledge Building (LKB). This system is de- signed for grammars specified in Type Description Language (TDL). 1 Introduction The coordination is an important linguistic phenomenon. It joins two or several com- pounds using conjunctions. However, there exist some cases where the elements composing a coordination structure are joined implicitly. This phenomenon interacts with many other syntactic phenomena, such as ellipsis and relatives. Therefore, there exist a large number of coordinated forms. To treat the different cases of the coordination phenomenon, we should use a relia- ble formalism. In fact, a great representation leads to a correct syntactic analysis. In this context, appears the HPSG [14]. The choice of this formalism is justified. It is a unification grammar characterized by a reliable modeling and a complete representa- tion of linguistic knowledge. Besides, HPSG proposes a modularized organization of linguistic knowledge. It minimizes the syntactic rules and attributes a great impor- tance to the lexicon. Therefore, our work aims to construct an HPSG grammar treating the simple forms of Arabic coordination, the interaction with ellipsis and relatives and some embedded forms. Thus, we start by proposing a typology classifying the coordinated construc- tions. Afterward, we adapted the HPSG grammar to represent the different forms of Arabic coordination. The established grammar was specified in TDL [12]. Indeed,