A formal language is a set of strings composed of symbols from a defined alphabet that follows specific syntactical rules or grammar. Unlike natural languages, which are used for everyday communication and can be ambiguous and variable, formal languages are precise and unambiguous. They are often used in mathematical logic, computer science, linguistics, and theoretical computer science. Key characteristics of formal languages include: 1. **Alphabet**: The basic set of symbols from which strings are formed.
Articles by others on the same topic
A formal language over a fixed finite alphabet is a set of finite words. Here contains every finite word over , including the empty word . A formal language may contain finitely or infinitely many such words.[ref]
For example, over contains ,
ab and aaabbb, but not abab. The notation specifies a set of permitted words; it does not itself give a running time for deciding membership. The empty language contains no words, whereas contains one.Concatenation of formal languages combines permitted words from two formal languages. Automata theory and computability theory ask which machine models can recognize such sets, while computational complexity theory asks what resources membership decisions require.
