Simulation of cosmological voids in Lambda greater than 0 Friedmann models

The present study of the formation and evolution of cosmological voids, in models constituted from nonrelativistic, pressureless matter and a nonzero cosmological constant Lambda, numerically simulates the growth of primordial density fluctuations from recombination to the present epoch and encompasses in its parameter survey (1) inflationary k = 0 models, (2) noninflationary models with k = +1 or -1, and (3) Lambda = 0 models. The formation of large-scale structures is modeled using a system of concentric spherical shells of equal mass; by imposing an appropriate condition at the edge of the system, the same model can be used to study bubble-like universes approximated by a regular lattice of identical voids separated by overdense regions. It is found difficult, if not impossible, to distinguish models of Lambda greater than 0 from those of Lambda = 0 on the basis of observations of galaxy kinematics. 80 refs