Dense network cores disproportionately drive epidemic spreading — targeted core removal is most effective
I = 0 | R = 0 | max k-core = —
The k-core of a network is the maximal subgraph where every node has at least k neighbors within the subgraph.
Inner cores (high k) are densely connected and act as super-spreaders. Seeding the epidemic in the core (orange) vs periphery (blue)
shows dramatically different outbreak sizes. Removing core nodes above a threshold (immunization) collapses the core structure and
reduces R₀. Node color encodes k-shell index.