Using Closure Properties to Show Nonregularity

Proving languages are not regular using closure properties

Using our knowledge of a few nonregular languages, we can conclude that other languages are nonregular merely by using the closure properties of regular languages. For example, the language NOTPRIME ($\{a^n\}$ where $n$ is not prime) is not regular. If it were, then its complement, PRIME ($\{a^n\}$ ...