  The initial production and dynamical expansion of hot spherical nuclei are
examined as the first stage both in the projectile-multifragmentation and in
central collision processes. The initial temperatures, which are necessary for
entering the adiabatic spinodal region, as well as the minimum temperatures and
densities, which are reached in the expansion, significantly differ for hard
and soft equations of state. Additional initial compression, occurring in
central collisions leads most likely to a qualitatively different
multifragmentation mechanism. Recent experimental data are discussed in
relation to the results of the proposed model.
