We investigate the efficiency and stability of R&D networks in a model with network-dependent indirect spillovers. We show that the efficient network structure critically depends on the marginal cost of R&D collaborations. When the marginal cost is low, the complete graph is efficient, while...

No abstract received.

No abstract received.

The excessive increase of leverage, i.e. the abuse of debt financing, is considered one of the primary factors in the default of financial institutions since it amplifies potential investment losses. On the other side, portfolio diversification acts to mitigate these losses. Systemic risk...

A model of Brownian particles with the ability to take up energy from the environment, to store it in an internal depot, and to convert internal energy into kinetic energy of motion, is discussed. The general dynamics outlined in Section 2, is investigated for the deterministic and stochastic...

A stochastic theory is presented for nucleation and growth of clusters in a finite system. We consider a discrete cluster distribution for which the free energy and the equilibrium probability distribution are derived. The cluster growth and shrinkage occurs by the attachment/evaporation of free...