## Consists of: (∑,

*N*,*R*,*e*S)- ∑: finite set of
*terminals*(character set) *N*: finite set of*nonterminals**R*: finite set of rules of the form “*A**e*”, where*A*∈*N*,*e*is a*parsing expression*.*e*S: a parsing expression called the*start expression*.

- ∑: finite set of