Geodesic structure of spacetime near singularities

Geodesic flows emanating from an arbitrary point $\mathcal{P}$ in a manifold $\mathcal{M}$ carry important information about the geometric properties of $\mathcal{M}$. These flows are characterized by Synge’s world function and van Vleck determinant - important bi-scalars that also characterize quantum description of physical systems in $\mathcal{M}$. If $\mathcal{P}$ is a regular point, these bi-scalars have well known expansions around their flat space expressions, quantifying $\mathit{\text{local}}\mathit{\text{flatness}}$ and equivalence principle. We show that, if $\mathcal{P}$ is a singular point, the scaling behavior of these bi-scalars changes drastically, capturing the non-trivial structure of geodesic flows near singularities. This yields remarkable insights into classical structure of spacetime singularities and provides useful tool to study their quantum structure.