Basic Fourier series: convergence on and outside the q-linear grid
  A q-type Holder condition on a function f is given in order to establish (uniform) convergence of the corresponding basic Fourier series S_q[f] to the function itself, on the set of points of the q-linear grid. Furthermore, by adding others conditions, one guaranties the (uniform) convergence of S_q[f] to f on and "outside" the set points of the q-linear grid. 
J. L. Cardoso