Comment on “Nontrivial geometries: Bounds on the curvature of the universe”

The paper “Nontrivial geometries: Bounds on the curvature of the universe” [L. Mersini-Houghton, E. Kafexhiu, Nontrivial geometries: bounds on the curvature of the universe, Astropart. Phys. 29 (2008) 167 [0705.0332v1 [astro-ph]]] seeks to study the effect of non-trivial spatial curvature in homogeneous and isotropic models. We note that the space considered is not homogeneous, and that the equations of motion used are inconsistent with the metric. Also, we explain why the spatial curvature of homogeneous and isotropic spacetimes always evolves like 1 / a 2 , contrary to the central assumption of [1].