A Wordnet from the Ground Up

4.3. Generic Patterns Verified Statistically 117The unmarked order in a Polish sentence is Subject-Verb-Object, so simple lexicosyntacticpatterns might work similarly as in English. Anything more complicated,such as rich morphosyntactic agreement or even slightly relaxed word/phrase order(usually meaning-preserving) need additional work. We put more emphasis on themorphosyntactic description of pattern elements in terms of the tagset in the IPI PANCorpus [IPIC] (Przepiórkowski, 2004). The categories include a finer-grained list ofparts of speech and dozens of values of several grammatical categories (case, number,gender, person, degree, tense, aspect).Multiword LU occurrences also get morphosyntactic descriptions – see Section 3.4.5how this worked with MSR extraction. The linear order of LUs in a Polish sentenceneed not be correlated with their role in asymmetric lexico-semantic relations. Forexample, many patterns mark the hypernym and the hyponym by different cases, whiletheir relative positions change. We could generate specific patterns for all differentcombinations, but we can also look for generalization of a group of patterns based onthe morphosyntactic properties.Following Espresso, patterns are flat and describe a sentence as a sequence of wordforms or at most groups of word forms. They are not based on any deeper descriptionof the syntactic structure. The alphabet comprises three types of symbols:• an asterisk symbol * indicating place for zero or more tokens,• root,• and markers of matching locations, variables in Espresso, which require morestructure in Estratto.The empty symbol represents any LU (represented by any of its word forms). Theroot represents an actual basic morphological word form of an LU and its grammaticalclass. This takes care of the likely ambiguity. A matching location includes a partialmorphosyntactic description (a reduced version of the IPIC morphosyntactic tag, withselected category values) that represents all LUs with a matching morphosyntacticdescription. Grammatical classes in IPIC are too fine-grained. We introduced “macro”symbols, such as noun that represents jointly all grammatical classes: substantives,gerunds, foreign nominals and depreciative nouns.As in Espresso, there are always two matching locations, at the beginning and theend of a pattern. Patterns do not describe the left and right context of a potentialinstance.Matching locations also encode the roles of both LUs identified, for example:(hypo:subst:nom) jest (hyper:subst:inst)(hyper:subst:inst) jest (hypo:subst:nom)