Language of Balanced Parentheses
- Base Case: The empty string ε is in the language LLL.
- Recursive Step:
- If xxx is in LLL, then (x) is in LLL.
- If xxx and yyy are in LLL, then xyxyxy is in LLL.
- Closure: A string is in LLL if and only if it can be derived from the base case using a finite number of applications of the recursive step.