Multiple choice

If the strings of a language L can be effectively enumerated in lexicographic (i.e., alphabetic) order, which of the following statements is true?

  1. L is necessarily finite

  2. L is regular but not necessarily finite

  3. L is context free but not necessarily regular

  4. L is recursive but not necessarily context free

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Since L can be effectively enumerated so L has to be regular, but is doesn't mean that the decisions are finite.