The way diseases spread through schools, epidemics through countries and viruses through the Internet is crucially determining their risk. Although each of these threats has its own characteristics, its underlying network determines the spreading. To restrain the spreading, a widely used...

One of the challenges in fighting cybercrime is to understand the dynamics of message propagation on botnets, networks of infected computers used to send viruses, unsolicited commercial emails (SPAM) or denial of service attacks. We map this problem to the propagation of multiple random walkers...

Power grids, road maps, and river streams are examples of infrastructural networks which are highly vulnerable to external perturbations. An abrupt local change of load (voltage, traffic density, or water level) might propagate in a cascading way and affect a significant fraction of the network....

We introduce uncertainty in our general equilibrium model with multi-member groups, following the classical state-space approach of Arrow- Debreu. A host of new interesting economic issues emerge. First, risk averse agents can attempt to insure themselves through markets or through mutual...

\begin{abstract} We analyse time series of CDS spreads for a set of major US and European institutions on a period overlapping the recent financial crisis. We extend the existing methodology of \emph{$\varepsilon$-drawdowns} to the one of \emph{joint $\varepsilon$-drawups}, in order to estimate...

We investigate whether the set of Kreps and Porteus (1978) preferences include classes of preferences that are stationary, monotonic and well-ordered in terms of risk aversion. We prove that the class of preferences introduced by Hansen and Sargent (1995) in their robustness analysis is the only...

With our knowledge of the universe, we have sent men to the moon. We know microscopic details of objects around us and within us. And yet we know relatively little about how our society works and how it reacts to changes brought upon it. Humankind is now facing serious crises for which we must...

We introduce a general framework for models of cascade and contagion processes on networks, to identify their commonalities and differences. In particular, models of social and financial cascades, as well as the fiber bundle model, the voter model, and models of epidemic spreading are recovered...

We ask whether a PAYG-financed social security system is welfare improving in an economy with idiosyncratic and aggregate risk. We argue that interactions between the two risks are important for this question. One is a direct interaction in the form of a countercyclical variance of idiosyncratic...

In this paper we focus on diversity-induced resonance, which was recently found in bistable, excitable and other physical systems. We study the appearance of this phenomenon in a purely economic model of cooperating and defecting agents. Agent's contribution to a public good is seen as a social...