Encoding information on adjectives in a lexical-semantic net for computational applications

The goal of this paper is to describe how the EuroWordNet framework for representing lexical meaning is being modified within an Italian National Project in order to include information on adjectives. The focus is on the 'new' semantic relations being encoded and on the revisions we have made to the EuroWordNet Top Ontology structure. We also briefly discuss the utility of the information which is being encoded for computational applications. I n t r o d u c t i o n The Princeton WordNet (henceforth WN) is a lexical semantic network in which the meanings of words are represented in terms of their conceptual and lexical relations to other words. The basic notion around which it is developed is that of a synset (synonyms set), i.e. a set of words with the same Part-of-Speech (PoS) that can be interchanged in a certain context. Various conceptual and lexical relations are then encoded between synsets of the same PoS: e.g., hyponymy, antonymy, meronymy, etc. (Miller et al. 1990; Fellbaum 1998b). Within the EuroWordNet (henceforth EWN) project I a similar (multilingual) lexical resource was developed, retaining the basic underlying design of WN, but enriching the set of lexicalsemantic relations to be encoded for nouns and verbs in various ways 2, in order to obtain a maximally re-usable resource for computational applications. Thus, a) cross-PoS (xPos) relations were added so that different surface realizations of similar concepts within and across languages could be matched (e.g., the noun research and the verb to research could be linked as 1 EWN was a project in the EC Language Engineering (LE-4003 and LE-8328) programme. In a first phase, the partners involved were the University of Amsterdam (coordinator); the Istituto di Linguistica Computazionale, CNR, Pisa; the Fundacion Universidad Empresa (a cooperation of UNED, Madrid, Politecnica de Catalunya, Barcelona, and the University of Barcelona); the University of Sheffield; and Novell Linguistic Development (Antwerp), changed to Lemout & Hauspie during the project. In a further phase, the database was extended with German, French, Estonian and Czech. Complete information on EWN can be found at its web site: http://www.hum.uva.nl/~ewn/. 2 Adjectives and adverbs were encoded in EWN only as targets of relations from nouns and verbs.