A Wordnet from the Ground Up

26 Chapter 2. Building a Wordnet Core2.2 The Lexico-semantic RelationsA set of lexico-semantic relations that underlie a wordnet is its most distinguishingdesign consideration. While languages with different typology require subtly differentsets, many relations carry well across types. For clear portability reasons, we decidedto stay as close as possible to the PWN set of relations, and to include a few fromthe EuroWordNet [EWN] project (Vossen, 2002). The current version of plWordNetsupports the following relations (the last two come from EWN):• synonymy,• antonymy,• conversion,• hypernymy/hyponymy,• troponymy,• holonymy/meronymy,• relatedness,• pertainymy,• fuzzynymy.We have kept the division of LUs into grammatical classes (parts of speech, as inPWN): nouns, verbs and adjectives. Relations other than relatedness and pertainymyconnect LUs in the same class. Some relations are symmetrical (for example, if A isan antonym of B, then B is an antonym of A) or are mutual inverses (for example,a hyponymy pair is always the inverse of the corresponding hypernymy pair), whileothers are not (for example, holonymy: a spoke is part of a wheel, but not everywheel has spokes). We refer to both these properties of semantic relations by thegeneral term reversibility, and assign it the value “+” or “−”. The value is “−”only for meronymy-holonymy pairs and troponymy-hypernymy pairs, the latter becauseplWordNet distinguishes troponymy from hyponymy – see Section 2.2.2.Following EWN, we have defined substitution tests for each relation. The tests aremeant to be a tool that illustrates the definition, facilitates identification of relation instancesand promotes consistency of decisions among linguists. The tests are presentedin Appendix A.Similar to other wordnets, among them PWN and EWN, lexico-semantic relationsare defined in two domains: LUs and synsets. Hyperhymy/hyponymy and