Prefix-primitive annihilators of languages under some operations

This paper studies some properties of prefix-primitive annihilators of languages under the catenation, shuffle product and bi-catenation operations. We prove that for every finite language L under the catenation operation, the left prefix-primitive annihilator of L is not equal to the right prefix-primitive annihilator of L, the left prefix-primitive annihilator of languages is not regular for any finite language, and the left prefix-primitive annihilator of any thin languages is not empty. Moreover, we also characterize the prefix-primitive annihilators of non-empty language under the shuffle product and bi-catenation operations over the alphabet with two letters.