Connections between the semantic layer of Walenty valency dictionary and P l W ord N et (2019)

Abstract: In this paper we discuss how Walenty is using PLWORDNET to represent semantic information. We decided to use PLWORDNET lexical units and synsets to describe both the predicate meaning and the semantic fields of its arguments. The original design decision required some further refinement caused by the structure of PLWORDNET and complex relations between arguments.

## introduction walenty, a comprehensive valency dictionary of polish developed at the institute of computer science, polish academy of sciences (ics pas), is created to a large degree as a part of clarin-pl @xcite . 1 it was meant to be used both by computer programs (e.g. it is employed by two parsers of polish, polfie foot_1 @xcite and świgra foot_2 @xcite ) and by linguists. walenty is composed of two main layers: syntactic and semantic. the syntactic layer was described in @xcite @xcite , whereas @xcite focuses on its phraseological component. on the other hand, the semantic layer was sketched in @xcite . the semantic layer of walenty is strictly connected with plwordnet @xcite , one of two polish wordnets. 4 plwordnet describes the meaning of a lexical unit by placing this unit in a network of relations (such as synonymy, hypernymy, meronymy, etc.). in this paper we want to focus on how semantic layer of walenty was influenced by plwordnet and its structure. ## related works there exist valency dictionaries connecting syntactic and semantic information about predicates and their arguments. the most famous is framenet foot_4 @xcite based on a theory called frame semantics @xcite . it is organised around the notion of a semantic frame representing a situation. a semantic frame is evoked by lexical units representing corresponding meanings of words (not only verbs). frames are lists of semantic roles called frame elements @xcite . framenet contains about 800 hierarchically organised frames evoked by 10 000 lexical units. frames are organised in a hierarchy which relates lexical units evoking them. apart from a hierarchy, frames are organised into scenarios. nevertheless, framenet lexical units are not related to a wordnet (in particular, princeton wordnet, @xcite ) and create independent structure foot_5 . another important valency dictionary is verb-net foot_6 @xcite based on the classification of verbs by @xcite . each verb class in verbnet is completely described by semantic roles, selectional restrictions on the arguments, and frames consisting of a syntactic description and semantic predicates with a temporal function. verbnet describes about 5250 senses of 3800 verb lemmas. each verbal sense in verbnet may refer to a set of wordnet senses that captured the meaning appropriate to the corresponding levin's class a third one, verbalex @xcite is connected with the czech wordnet @xcite . valency frames are connected with whole synsets, not particular lexical units. the semantic characteristic of arguments has two level representation and consists of a set of semantic roles including 40 elements from eurowordnet top ontology @xcite and more precise semantic types including specific literals (lexical units) from the set of princeton wordnet base concepts with relevant sense numbers. semantic types correspond to selectional restrictions/preferences. on the other hand, the frames are connected to levin's classes and hence with verbnet. figure 1 presents an exemplary entry of ver-balex. a frame corresponds to a synset containing five lexical units, but only three of them can be used in 1 as other two do not follow the same syntax. there exist some polish valency dictionaries as well. the most important are @xcite @xcite . only the first one includes semantic information, i.e. abstract selectional restrictions (cf. figure 2 , e.g. np 1 a has to have 'anim' property, while np 2 a has to have 'abstr' property). a corpus-based dictionary including some purely syntactic valency information is @xcite . 'like' in polański's valency dictionary the representation language of walenty is in general universal w.r.t. parts of speech. each lexical entry is identified by its lemma (e.g. verb gniewa ć 'irritate' noun gniew 'anger', 'irritation' or adjective gniewny 'angry', 'irritated'). on the syntactic level, each entry is divided into subentries according to its grammatical properties. reflexive mark, aspect (both only for verbs), predicativity (only for adjectives and adverbs) and negativity are taken into account. for instance, the entry gniew has exactly one subentry gniew (, ,), whereas gniewa ć has two subentries gniewa ć (_, , imperf) and gniewa ć si ę (_, , imperf). each subentry may have any number of syntactic valency schemata foot_7 assigned, each being a set of syntactic positions. a syntactic position is a set of phrase types -if two morphosyntactically different phrases may occur coordinated, they are taken to be different realisations of the same position @xcite . labels are used to distinguish special argument positions -subject and object (if they occur). in walenty we decided that subject and object syntactic positions 9 are marked only for verbs. however, there exist theories, e.g. generative ones, in which nouns, at least some of them (derived nominals), have (deep) subjects and objects @xcite . the required information can be inferred from dependencies between derivationally connected entries as both syntactic positions represent the same argument, cf. section 6. additional label head was introduced in order to represent a non-local control dependency between the head of an adjective and its infinitival argument (e.g. szukaj ą kompozytorów gotowych tworzyć z nimi nowoczesny teatr. '[they] are looking for composers [who are] ready to create a modern theater with them.'). this matter, similarly as other issues specific for syntax of nonverbal predicates, goes beyond the scope of this article. ## semantic layer the semantic layer is composed of semantic frames. each frame is a set of semantic arguments represented as pairs semantic role, selectional preferences . the set of semantic roles is presented in figure 3 -they have colours assigned to them in a fixed way. more information about semantic roles in walenty is included in @xcite . we assume that there cannot be two identical frames for a single entry, as otherwise there would be no way to distinguish between their meanings. this requirement does not concern frames identified by multi-word lemmas if they correspond to a different meaning. 9 representation of subject and object in walenty was described in (przepiórkowski et al., 2014a). ## common frames representation of verbs, nouns and adjectives does not differ on semantic level. what is important, derivationally connected entries of different poses are attached to the same frames. this is important for a correct interpretation of paraphrase. for historical reasons, this does not concern aspectual pairs. it is worth noting that verbnet and verbalex are focused solely on verbs, whereas framenet and pdt-vallex concern nouns and adjectives as well. let us consider the noun gniew 'anger' derivationally connected with the verb gniewa ć si ę 'be angry', cf. figure 7 (4 out of 15 schemata are visualised on the figure). please note that the frame presented in figures 6 and 7 is connected with the six plwordnet lexical units: gniewny-1, gniewać-1, gniewać si ę-1, gniewać si ę-2, gniew-1 and gniew-2. this means that the frame is shared by three entries: gniewa ć, gniew and gniewny, and units representing the meaning of the current entry is written in bold. plwordnet contains lexical units having multi-word lemmas, and we decided to adapt this approach in walenty. the semantic frame for the idiom kraść całusa 'steal a kiss' is presented in figure 8 . the fact that the frame is linked to an idiom is marked with a white rectangle with lemma inside; a lexicalised dependant is marked white as well. such phraseology appears for nonverbal entries as well foot_9 . we have chosen an idiom having both verbal and nominal realisation, which is not a typical case. lus identifying such idioms have multi-word lemmas composed of a lemma of the main predicate (here: the verb kra ś ć 'steel') and its syntactically dependant part (here: the noun całus 'kiss' in accusative) in a syntactically coherent way, see figure 8 . the structure of such a lemma could be more complicated, e.g. płakać nad rozlanym mlekiem 'cry over spilt milk', cf. 9. similarly as in the general case, such lemma can be present in plwordnet or added in walenty. ## conclusions and future works this article describes the relations between two polish language resources plwordnet and walenty valency dictionary. the relations appear on two levels. first, plwordnet lexical units are connected to each semantic valency frame as their meaning identifiers. in particular, this concerns lus with multi-word lemmas. moreover, synsets (represented by lus) are used to represent selection preferences of arguments. walenty is based on plwordnet version 2.1. therefore, one of the main future tasks is to update the connection to the current version of plword-net. this will be a very complicated task due to the fact that the changes in plwordnet are deep, which sometimes may cause a shift of the meaning of a particular lu. we plan to apply mappings between lus from the source and the target plwordnet versions and estimate their reliability comparing their neighbourhood in the net. the special attention should be paid to to the lus deleted from the plwordnet. on the other hand, we plan to automatically check, for all lus added by walenty developers, whether there exist relevant new plwordnet units. the operation will be based on the synonymy/hypernymy relations. the whole procedure aims at maximal limitation of manual work. in further future we want to connect semantically related frames of different entries in a hierarchical structure similar to hypernymy. this may involve unification of frames into a framenet-like hierarchy with inheritance. we are also interested in enriching the semantic layer with other semantic relations like presupposition or causation. the (morpho)syntactic level will not be influenced by these changes.