  A result of Bapat and Sivasubramanian gives the inertia of the distance
squared matrix of a tree. We develop general tools on how pendant vertices and
degree 2 vertices affect the inertia of the distance squared matrix and use
these to give an alternative proof of this result. We further use these tools
to extend this result to certain families of unicyclic graphs, and we explore
how far these results can be extended.

Combinatorics