Abstract:
It is proved that if a weighted space $L_2(h)$ on the interval $(-1;1)$ admits an unconditional basis of exponentials, and the entire function that generates this basis satisfies a certain condition, then the space $L_2(h)$ is isomorphic (as a normed space) to the usual space $L_2$.
Keywords:Series of exponentials, unconditional basis, Hilbert space, entire functions.