Caption: 2-dimensional space analog of possible 3-dimensional space geometries in simple GR models of the universe: i.e., the FLRW models and the FLRW-Λ models.
Features:
Ω is a sort of dimensionless density for the universe.
where ρ is density and ρc is the critical density:
But Omega if greater than 1, stays greater than 1 for all time, if less than 1, stays less than 1 for all time, if exactly 1, stays exactly 1 for all time, in pure Friedmann equation models whether Λ=0 or Λ≠0.
These people believe the models can only be extended to our pocket universe.