  Numerous approaches study the vulnerability of networks against social
contagion. Graph burning studies how fast a contagion, modeled as a set of
fires, spreads in a graph. The burning process takes place in synchronous,
discrete rounds. In each round, a fire breaks out at a vertex, and the fire
spreads to all vertices that are adjacent to a burning vertex. The selection of
vertices where fires start defines a schedule that indicates the number of
rounds required to burn all vertices. Given a graph, the objective of an
algorithm is to find a schedule that minimizes the number of rounds to burn
graph. Finding the optimal schedule is known to be NP-hard, and the problem
remains NP-hard when the graph is a tree or a set of disjoint paths. The only
known algorithm is an approximation algorithm for disjoint paths, which has an
approximation ratio of 1.5.
