Editing Context-sensitive grammar (section)

== Kuroda normal form ==
Every context-sensitive grammar which does not generate the empty string can be transformed into a [[weak equivalence (formal languages)|weakly equivalent]] one in [[Kuroda normal form]]. "Weakly equivalent" here means that the two grammars generate the same language. The normal form will not in general be context-sensitive, but will be a [[noncontracting grammar]].<ref>{{cite journal | first=Sige-Yuki | last=Kuroda | author-link=S.-Y. Kuroda | title=Classes of languages and linear-bounded automata | journal=Information and Control | volume=7 | number=2 | pages=207–223 | date=June 1964 | doi=10.1016/s0019-9958(64)90120-2| doi-access=free }}</ref><ref>{{cite book |last1=Mateescu | first1=Alexandru |last2=Salomaa|first2=Arto |author-link2=Arto Salomaa|editor1-first=Grzegorz| editor1-last=Rozenberg|editor-link1=Grzegorz Rozenberg |editor2-first=Arto| editor2-last=Salomaa |editor-link2=Arto Salomaa|title=Handbook of Formal Languages. Volume I: Word, language, grammar |publisher=Springer-Verlag |year=1997 |pages=175–252 |chapter=Chapter 4: Aspects of Classical Language Theory |isbn=3-540-61486-9}}, Here: Theorem 2.2, p. 190</ref>

The Kuroda normal form is an actual normal form for non-contracting grammars.