Enlargement of a void in the expanding universe

In the Einstein-de Sitter model, the spherically symmetric less-dense perturbation is investigated with an aim to discuss the observed void in distribution of galaxies. In the nonlinear regime, the enlargement of the perturbed region occurs. For the neutrino dominated model, the enlargement of the void of nucleon number is estimated. It is argued also that the cellular structure in the galaxy distribution might be explained by the compression of matter squeezed between the expanding voids. (author)