Asymmetric truncated Toeplitz operators equal to the zero operator
  Asymmetric truncated Toeplitz operators are compressions of multiplication operators acting between two model spaces. These operators are natural generalizations of truncated Toeplitz operators. In this paper we describe symbols of asymmetric truncated Toeplitz operators equal to the zero operator. 
Joanna Jurasik and Bartosz {\L}anucha
math.FA