Editing Theory of computation (section)

==== Formal language theory ====
{{main|Formal language}}
[[Image:Chomsky-hierarchy.svg|thumb|right|200px|alt=The Chomsky hierarchy|Set inclusions described by the Chomsky hierarchy]]
Formal language theory is a branch of mathematics concerned with describing languages as a set of operations over an [[Alphabet (formal languages)|alphabet]]. It is closely linked with automata theory, as automata are used to generate and recognize formal languages. There are several classes of formal languages, each allowing more complex language specification than the one before it, i.e. [[Chomsky hierarchy]],<ref>{{cite journal |doi=10.1109/TIT.1956.1056813 |s2cid=19519474 |title=Three models for the description of language |date=1956 |last1=Chomsky |first1=N. |journal=IEEE Transactions on Information Theory |volume=2 |issue=3 |pages=113–124 }}</ref> and each corresponding to a class of automata which recognizes it. Because automata are used as models for computation, formal languages are the preferred mode of specification for any problem that must be computed.