Mutual Reachability

Mutual reachability combines the original metric distance between two points with their core distances.

For an edge (u, v) at target k, the weight is:

\[max(core_k(u), core_k(v), d(u, v))\]

This weight is what Core-SG uses to extract the target MST. Changing k changes core_k and therefore changes the reweighted support graph.