The structure of a society depends, to some extent, on the incentives of the individuals they are composed of. We study a stylized model of this interplay, that suggests that the more individuals aim at climbing the social hierarchy, the more society's hierarchy gets strong. Such a dependence is...

The recent credit crisis of 2007/08 has raised a debate about the so-called knife-edge properties of financial markets. The paper contributes to the debate shedding light on the controversial relation between risk-diversification and financial stability. We model a financial network where assets...

This paper provides a mapping from portfolio risk diversification into the pairwise correlation between portfolios. In a finite market of uncorrelated assets, portfolio risk is reduced by increasing diversification. However, higher the diversification level, the greater is the overlap between...

The paper clarifies the link between changes in risk aversion and the effect on the consumption discount rate. In a general framework that can cope with various forms of uncertainty, it is shown that the response of the consumption discount rate to a change in risk aversion depends on some...

While new forms of attacks are developed every day to compromise essential infrastructures, service providers are also expected to develop strategies to mitigate the risk of extreme failures. In this context, tools of network science have been used to evaluate network robustness and propose...

The flow of granular material, like sand, presents many intriguing effects in particular when it is shaken, poured or sheared. Here, the granular medium is modelled by a packing of elastic spheres and simulated via molecular dynamics. Dissipation of energy and shear friction at collisions are...

The propagation of a crack in an isotropic elastic medium is treated as a moving boundary problem. Linear stability analysis shows that for the stretched membrane with a central, initially circular hole all modes are stable. On the other hand all modes are unstable for a two-dimensional...

We describe the contact network of granular packings by a frustrated lattice gas that contains steric frustration as esential ingredient. Two transitions are identified, a spin glass transition at the onset of Reynolds dilatancy and at lower densities a percolation transition. We describe the...

We present various lattice Boltzmann models which reproduce the effects of rough walls, shear thinning and granular flow. We examine the boundary layers generated by the roughness of the walls. Shear thinning produces plug flow with a sharp density contrast at the boundaries. Density waves are...