Number partitioning as random energy model

Number partitioning is a classical problem from combinatorial optimisation. In physical terms it corresponds to a long range anti-ferromagnetic Ising spin glass. It has been rigorously proven that the low lying energies of number partitioning behave like uncorrelated random variables. We claim that neighbouring energy levels are uncorrelated almost everywhere on the energy axis, and that energetically adjacent configurations are uncorrelated, too. Apparently there is no relation between geometry (configuration) and energy that could be exploited by an optimization algorithm. This ``local random energy'' picture of number partitioning is corroborated by numerical simulations and heuristic arguments.Comment: 8+2 pages, 9 figures, PDF onl

Cyber Insurance: recent advances, good practices & challenges

The aim of this ENISA report is to raise awareness for the most impact to market advances, by shortly identifying the most significant cyber insurance developments for the past four years – during 2012 to 2016 – and to capture the good practices and challenges during the early stages of the cyber insurance lifecycle, i.e. before an actual policy is signed, laying the ground for future work in the area