UoL/CM3060 Natural Language Processing/Week 7/Week 7 Notes.md

Lexical semantics

The meaning of words

NLP Tasks

• Classifications tasks (e.g. spam detection)
• Sequence tasks (e.g. text generation)
• Meaning tasks. We study meaning in this section

Useful for:

• Information retrieval
• Question answering
• Topic modeling

What do words mean?

• Look in a dictionary

WordNet

A lexical database:

• Nodes are synsets (sets of synonyms)
• Correspond to abstract concepts
• Polyhierarchical structure, looks like a tree, but is flexible, nodes can have more than one parent.

Using WordNet we can programmatically:

• Identify hyponyms (child terms) and hypernyms (parent terms, we go up the tree for more general terms)
• Measure semantic similarity