Abstract:
We find the greatest lower bound for the type of an entire function of order
$\rho\in(0,1)$ whose sequence of zeros lies on one ray and has prescribed
lower and upper $\rho$-densities. We make a thorough study of the dependence
of this extremal quantity on $\rho$ and on properties of the distribution
of zeros. The results are applied to an extremal problem on the radii
of completeness of systems of exponentials.
Keywords:extremal problems, type of entire function, upper and lower densities of zeros,
completeness of systems of exponentials.