Note on a result of Kerman and Weit
  A result in \cite{Ker-Weit} states that a real valued continuous function $f$ on the circle and its nonnegative integral powers can generate a dense translation invariant subspace in the space of all continuous functions on the circle if $f$ has a unique maximum or a unique minimum. In this note we endeavour to show that this is quite a general phenomenon in harmonic analysis. 
Swagato K. Ray and Rudra P. Sarkar
math.FA