Systems of Dilated Functions: completeness, minimality, basisness
  We discuss completeness, minimality, and basisness, in $L^2[0, \pi]$ and $L^p[0, \pi]$, $p \neq 2$, of dilated systems $u_n(x) = S(nx)$, $n \in \mathbb{N}$, where $S$ is a trigonometric polynomial   $S(x) = \sum_{k = 0}^m a_k \sin(kx), \quad a_0 a_m \neq 0.$   We will present some results and mention a few unsolved questions. 
Boris Mityagin
math.CA