Mapping Wordnets on the Fly with Permanent Sense Keys (2023)

Abstract: Most of the major databases on the semantic web have links to Princeton WordNet (PWN) synonym set (synset) identifiers, which differ for each PWN release, and are thus incompatible between versions. On the other hand, both PWN and the more recent Open English Wordnet (OEWN) provide permanent word sense identifiers (the sense keys), which can solve this interoperability problem. We present an algorithm that runs in linear time, to automatically derive a synset mapping between any pair of Wordnet versions that use PWN sense keys. This allows to update old WordNet links, and seamlessly interoperate with newer English Wordnet versions for which no prior mapping exists. By applying the proposed algorithm on the fly, at load time, we combine the Open Multilingual Wordnet (OMW 1.4, which uses old PWN 3.0 identifiers) with OEWN Edition 2021, and obtain almost perfect precision and recall. We compare the results of our approach using respectively synset offsets, versus the Collaborative InterLingual Index (CILI version 1.0) as synset identifiers, and find that the synset offsets perform better than CILI 1.0 in all cases, except a few ties.

## introduction all the available multilingual wordnets @xcite and important knowledge bases on the semantic web @xcite @xcite were originally linked to different versions of princeton wordnet (pwn) @xcite , using version-specific synset offsets @xcite , which differ between releases, so mappings are necessary for interoperation, and for updating to a later english wordnet versions. many of these resources have been remapped to wordnet 3.0 or wordnet 3.1, using offset to offset mappings obtained by relaxation labelling @xcite , offset to ili (interlingual index) mappings @xcite @xcite , sensekey to sensekey mappings (wordnet-team, 2010, sensemap), and offset to offset mappings relying on sense key persistence @xcite . contrary to synset offsets, the sensekeys persist across database versions @xcite , and can thus support the derivation of mappings with high precision and recall. pwn sensekeys (wordnet-team, 2010, senseidx) are composite database keys representing one particular word sense. they consist in the concatenation of the identifiers for the corresponding lemma and its lexfile, lex_id, and eventually head adjective (see examples in sections 2.1, 3.2 and 4.2). each pwn version includes an index.sense file, linking the sense keys to their corresponding synset offsets. however, the necessary mappings between synsets linked to different pwn versions are not always available, either because a resource is too new, or has too few users to justify the production of a mapping. this causes potentially long delays for interoperability, which may remain impossible as long as no relevant mapping exists. for example, edition 2022 of the open english wordnet (oewn foot_0 ) @xcite was released recently, and the wndb foot_1 project has also published the same data in a pwn-compatible format (including the relevant index.sense). these two variants of the oewn 2022 edition use different, mutually incompatible synset offsets; no mapping exists for neither yet, and no known project currently aims to produce such mappings. on the other hand, oewn has adopted pwn sensekeys as its main sense identifier, so it is easy to extract a sense index from the database, and almost instantly produce a sensekey-based mapping, since this only requires joining the index.sense of the relevant wordnet versions. therefore, we propose to carry out the mapping process on the fly, whenever loading wordnets that are linked to different english wordnet (pwn or oewn) versions. ## discussion we have shown that mapping between different english wordnet versions is feasible in linear time, by relying on the stability of pwn sense keys. our method allows to transparently update the database links on-the-fly, to another english wordnet version, even though no prior mapping exists yet. this can benefit any database linked with an english wordnet, and enhance any downstream task that uses such a database. ## conclusion we presented an algorithm for mapping wordnets, that runs in linear time, thus moving the frontier of wordnet interoperability by allowing to almost instantly combine different database versions, for which no prior mapping exists. we illustrated this capability by combining the omw with oewn. other potential uses include seamlessly updating existing pwn links in any wordnet-linked semantic web database, to newer oewn versions. we saw how our mappings only lose tiny amounts of data when mapping multilingual wordnets, which indicates that the performance of this approach is comparable to the best results obtained with alternative strategies. now that oewn has adopted the original pwn sensekeys as main wordense identifier, we may expect that the proposed algorithm remains relevant with future oewn versions. however, if more wordnet resources start to use a common set of persistent identifiers like the pwn sensekeys, mappings could become unnecesary between these resources, as they would be natively interoperable.