Szeg\"o limit theorems for operators with almost periodic diagonals
  The classical Szeg\"o theorems study the asymptotic behaviour of the determinants of the finite sections $P_n T(a) P_n$ of Toeplitz operators, i.e., of operators which have constant entries along each diagonal. We generalize these results to operators which have almost periodic functions on their diagonals. 
Steffen Roch, Bernd Silbermann