Question

What is meant by theory of parsing in nlp?

Answer 1

In the context of natural language processing, the term parsing refers to the process of automatically analyzing a given sentence, viewed as a sequence of words, in order to determine its possible underlying syntactic structures. Parsing requires a mathematical model of the syntax of the language of interest. In this chapter, these mathematical models are assumed to be formal grammars. A formal grammar consists of a collection of rules that specify how elements of the language, e.g., words, may be combined to form sentences, and how sentences are structured. Rules may be concerned with purely syntactic information, such as grammatical functions, subject-verb agreement, word ordering, etc., but some models may also incorporate issues such as lexical semantics. There is a wide range of grammatical formalisms, which depend on various syntactic theories, and the structures that result from parsing, or parses , may differ substantially between one such formalism and another. Many formalisms specify the syntactic analysis of a sentence in terms of a phrase structure , which is an ordered, labeled tree that expresses hierarchical relations among certain groupings of words called phrases . An alternative representation is dependency structure , which indicates binary grammatical relations between words in a sentence. In contrast to these ‘deep’ representations, there are also ‘shallow’ ...