Key points are not available for this paper at this time.
In this paper causal geodesic completeness of Friedmann-Lema\^tre-Robertson-Walker (FLRW) cosmological models is analyzed in terms of generalized power expansions of the scale factor in coordinate time. The strength of the found singularities is discussed following the usual definitions due to Tipler and Kr\'olak. It is shown that while classical cosmological models are both timelike and lightlike geodesically incomplete, certain observationally allowed models which have been proposed recently are lightlike geodesically complete.
Fernández–Jambrina et al. (2006) studied this question.