Changes

In the linguistic literature, [nothing] is often represented by the symbol '''ε'''.

In the linguistic literature, [nothing] is often represented by the symbol '''ε'''.

The descriptions of the various Chomsky levels which follows are presented in reverse order, so as to work up from a simple case to a rather complicated case.

The descriptions of the various Chomsky levels which follow are presented in reverse order, so as to work up from a simple case to a rather complicated case.

===Level 3: regular grammar===

===Level 3: regular grammar===