ABSTRACT
This chapter starts with an introduction to formal grammars using the Chomsky hierarchy, followed by a discussion of the relationship between these grammars. The correlation of RNA secondary structure and context free grammar is shown. Recently, formal grammar techniques have been used to predict pseudoknots. Various types of grammar are further discussed, namely Parallel Communicating Grammar System, Pair Stochastic Tree Adjoining Grammar, Context Free Grammar, Multiple Context Free Grammar, Context Sensitive Grammar, Tree Augmented Grammar and Path Controlled Grammar.
