The role of shell crossing on the existence and stability of trapped
  matter shells in spherical inhomogeneous \Lambda-CDM models
  We analyse the dynamics of trapped matter shells in spherically symmetric
inhomogeneous \Lambda-CDM models. The investigation uses a Generalised
Lema\^itre-Tolman-Bondi description with initial conditions subject to the
constraints of having spatially asymptotic cosmological expansion, initial
Hubble-type flow and a regular initial density distribution. We discuss the
effects of shell crossing and use a qualitative description of the local
trapped matter shells to explore global properties of the models. Once shell
crossing occurs, we find a splitting of the global shells separating expansion
from collapse into, at most, two global shells: an inner and an outer limit
trapped matter shell. In the case of expanding models, the outer limit trapped
matter shell necessarily exists. We also study the role of shear in this
process, compare our analysis with the Newtonian framework and give concrete
examples using density profile models of structure formation in cosmology.
