  Superslow diffusion, i.e., the long-time diffusion of particles whose
mean-square displacement (variance) grows slower than any power of time, is
studied in the framework of the decoupled continuous-time random walk model. We
show that this behavior of the variance occurs when the complementary
cumulative distribution function of waiting times is asymptotically described
by a slowly varying function. In this case, we derive a general representation
of the laws of superslow diffusion for both biased and unbiased versions of the
model and, to illustrate the obtained results, consider two particular classes
of waiting-time distributions.
