So far we have given examples of only relatively simple grammars; every production

had a single variable on the left side. As we will see, such grammars are very

important, but the definition of grammar allows more general forms.

Consider the grammarG $=(\{$A$,$ B$,$ C$,$ D$,$ E$,$ S$\},\{$a$\},$ S$,$ P$)$