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Unformatted text preview: e a binary opposi-on or be at opposite ends of a scale •  long/short, fast/slow! •  Be reversives: •  rise/fall, up/down! !rise/fall! Dan Jurafsky Hyponymy and Hypernymy •  One sense is a hyponym of another if the first sense is more specific, deno-ng a subclass of the other •  car is a hyponym of vehicle •  mango is a hyponym of fruit •  Conversely hypernym/superordinate (“hyper is super”) •  vehicle is a hypernym of car •  fruit is a hypernym of mango Superordinate/hyper vehicle fruit furniture Subordinate/hyponym car chair mango Dan Jurafsky Hyponymy more formally •  Extensional: •  The class denoted by the superordinate extensionally includes the class denoted by the hyponym •  Entailment: •  A sense A is a hyponym of sense B if being an A entails being a B •  Hyponymy is usually transi-ve •  (A hypo B and B hypo C entails A hypo C) •  Another name: the IS ­A hierarchy •  A IS ­A B (or A ISA B) •  B subsumes A Dan Jurafsky Hyponyms and Instances •  WordNet has both classes and instances. •  An instance is an individual, a proper noun that is a unique en-ty •  San Francisco is an instance of city! •  But city is a class •  city is a hyponym of municipality...location...! 15 Word Meaning and Similarity Word Senses and Word Rela-ons Word Meaning and Similarity WordNet and other Online Thesauri Dan Jurafsky Applica1ons of Thesauri and Ontologies •  •  •  •  •  Informa-on Extrac-on Informa-on Retrieval Ques-on Answering Bioinforma-cs and Medical Informa-cs Machine Transla-on Dan Jurafsky WordNet 3.0 •  A hierarchically organized lexical database •  On ­line thesaurus + aspects of a dic-onary •  Some other languages availabl...
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This document was uploaded on 02/14/2014.

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