  We are concerned with the existence of global in time solutions to the Cauchy
problem for semi-linear Klein-Gordon equations with memory-type dissipation in
$\mathbb{R}^n$. In the first place, we consider the linearized equation:
applying the energy method in the Fourier space, we derive the point-wise
estimate of a solution in the Fourier space. However, we found that the
function in energy estimates has a mistake.
