Hankel Operators over Compact Abelian Groups
  Two variants of generalizations of Hankel operators to the case of linearly ordered abelian groups are considered, criteria of the boundedness and compactness of these operators are given, among them in terms of functions of bounded mean oscillation, the nonfredholmness of generalized Hankel operators is proved. Some applications to the theory of Toeplitz operators on groups are given. 
A. R. Mirotin and E. Yu. Kuzmenkova
math.FA