Skip to main content

Probabilistic Context-Free Grammars

  • Reference work entry
  • First Online:

Synonyms

PCFG

Definition

In formal language theory, formal grammar (phrase-structure grammar) is developed to capture the generative process of languages (Hopcroft and Ullman 1979). A formal grammar is a set of productions (rewriting rules) that are used to generate a set of strings, that is, a language. The productions are applied iteratively to generate a string, a process called derivation. The simplest kind of formal grammar is a regular grammar.

Context-free grammars (CFG) form a more powerful class of formal grammars than regular grammars and are often used to define the syntax of programming languages. Formally, a CFG consists of a set of nonterminal symbols N, a terminal alphabet Σ, a set P of productions (rewriting rules), and a special nonterminal S called the start symbol. For a nonempty set X of symbols, let X denote the set of all finite strings of symbols in X. Every CFG production has the form Sα, where SN and \(\alpha \in (N \cup \Sigma )^{{\ast}}\). That is,...

This is a preview of subscription content, log in via an institution.

Buying options

Chapter
USD   29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD   699.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Hardcover Book
USD   949.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Learn about institutional subscriptions

Recommended Reading

  • Durbin R, Eddy S, Krogh A, Mitchison G (1998) Biological sequence analysis. Cambridge University Press, Cambridge

    Book  MATH  Google Scholar 

  • Hopcroft JE, Ullman JD (1979) Introduction to automata theory, languages and computation. Addison-Wesley, Reading

    MATH  Google Scholar 

  • Lari K, Young SJ (1990) The estimation of stochastic context-free grammars using the inside-outside algorithm. Comput Speech Lang 4:35–56

    Article  Google Scholar 

  • Sakakibara Y (1997) Recent advances of grammatical inference. Theor Comput Sci 185:15–45

    Article  MathSciNet  MATH  Google Scholar 

  • Sakakibara Y (2005) Grammatical inference in bioinformatics. IEEE Trans Pattern Anal Mach Intell 27:1051–1062

    Article  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2017 Springer Science+Business Media New York

About this entry

Cite this entry

Sakakibara, Y. (2017). Probabilistic Context-Free Grammars. In: Sammut, C., Webb, G.I. (eds) Encyclopedia of Machine Learning and Data Mining. Springer, Boston, MA. https://doi.org/10.1007/978-1-4899-7687-1_669

Download citation

Publish with us

Policies and ethics