Editing Phrase structure grammar (section)

== History ==
In 1956, Chomsky wrote, "A phrase-structure grammar is defined by a finite vocabulary (alphabet) V<sub>p</sub>, and a finite set Σ of initial strings in V<sub>p</sub>, and a finite set F of rules of the form: X → Y, where X and Y are strings in V<sub>p</sub>."<ref>{{Cite journal |last=Chomsky |first=Noam |date=1956 |title=Three models for the description of language |url=https://chomsky.info/wp-content/uploads/195609-.pdf |journal=[[IRE Transactions on Information Theory]] |page=117|archive-url=https://web.archive.org/web/20230503111934/https://chomsky.info/wp-content/uploads/195609-.pdf |archive-date=2023-05-03 }}</ref>