0 votes 0 votes Define an operation $third$ on strings and languages as $third(a_1a_2a_3a_4a_5a_6...)=a_3a_6...$ with the appropriate extension of this definition to languages. Prove the closure of the family of regular languages under this operation. Theory of Computation peter-linz peter-linz-edition4 theory-of-computation regular-language closure-property + – Naveen Kumar 3 asked Apr 5, 2019 Naveen Kumar 3 294 views answer comment Share Follow See all 0 reply Please log in or register to add a comment.