A Wordnet from the Ground Up

104 Chapter 4. Extracting Relation Instancestarget nominal LUs not only with some constraints by also with the pairs of LUs infocus. That is why we used here the same set of 13285 nominal lemmas which wereselected for the construction of nominal MSR and the expansion of the core plWordNet(Section 3.4.5). From the set, we generated all possible pairs. We also reapplied themechanism of co-incidence matrix construction. Target LUs were assigned to rows,and patterns with the position NLU2 instantiated to subsequent target LUs were assignedto columns. The patterns were run with position 0 representing NLU1 3 .Given these assumptions, there is no need to test the presence of NLU1 in theIInne and TakichJak code (Figures 4.1–4.2). We refer the reader to Section 3.4.3for the details of JOSKIPI. IInne is implemented in two symmetrical parts joined byor for two configurations of the hyponym (NLU1) and hypernym (NLU2). The matrixconstruction requires that we start with the hyponym in position 0. In the first part, wefirst test if the potential NLU1 is nominative, then look to the right (till the end of thesentence) for the first verb word form or the first nominal LU and record its positionin variable $X. We test if it is a form of the verb być (to be) – any other verb or nounmeans that the sentence does not match the pattern. We look further to the right for thefirst verb or the first nominal LU, or a preposition (prep) that requires the instrumentalcase. The latter is necessary, because NLU2 in the pattern is only identified by the casevalue induced by the verb być. The token at position $Y is compared with the baseform with which the pattern was instantiated 4 . We also test its case and number.In the pattern TakichJak in Figure 4.2, the iteration goes in the opposite direction.Hyponyms now follow the hypernym, and we wanted to keep the same 〈hyponym,hypernym〉 order of the extracted LU pairs across all the patterns. After the caseof NLU1 has been tested, we look to the left till the beginning of the sentence forthe sequence taki jak (such as). Next, we test the tokens between 0 and $+2T –the position after jak – for the presence of only LUs of the specified grammaticalclasses plus the specified punctuation marks and conjunctions; this signal a coordinatesequence of noun phrases. Finally, NLU2 is sought further to the left, and tokensbetween it and taki are tested. Only modifiers are accepted there, including nounsand pronouns in the genitive case.The implementation of the other three patterns is similar.The patterns IInne, WTym and TakichJak are structurally very similar: a hypernymand a list of hyponyms. Also, a preliminary evaluation on a part of IPIC showed3 Multiword LUs were recognised during preprocessing and folded into a one-token representationwith the attribute and root set to the values proper for the whole LU. During matrix construction, eachtarget LU occupies exactly one token in the preprocessed representation of the corpus (Broda and Piasecki,2008b). Recognition of multiword LUs was limited to target LUs (all parts of speech) due to the labourintensityof their syntactic description.4 Technically, each column in the matrix is assigned its own copy of the pattern instantiated to theappropriate nominal LU as NLU2.