Fig. 2: Diagram operations.
From: Epidemic graph diagrams as analytics for epidemic control in the data-rich era
a EGD of Fig. 1. The two strongly connected components are highlighted by blue rectangles. b Diagram operation CUT isolates the strongly connected components, which become disjoint subdiagrams. The epidemic threshold is then the smallest among the thresholds of each subdiagram. c Under the weak-commutation condition, each subdiagram can be further reduced through (i) diagram operation SHRINK (top) and (ii) diagram operation ZIP (bottom), leading to two EGDs of SIS models. Their transition rates are renormalized by the diagram operations. d, e General rules of the three operations. Numbers refer to the steps to be performed for each operator; some of these steps are illustrated in (a–c) with the same numbers.
