Recent crises in the financial industry have shown weaknesses in the modeling of Risk-Weighted Assets (RWAs). Relatively minor model changes may lead to substantial changes in the RWA numbers. Similar problems are encountered in the Value-at-Risk (VaR)-aggregation of risks. In this article, we...

In this paper we extend results on optimal risk allocations for portfolios of real risks w.r.t. convex risk functionals to portfolios of risk vectors. In particular we characterize optimal allocations minimizing the total risk as well as Pareto optimal allocations. Optimal risk allocations are...

For a class of point processes including nonhomogeneous Poisson processes, some Cox processes and some processes of non-Poisson type, the question of existence and construction of complete and sufficient statistics is investigated. The results are based on the generalization of some results from...

The question of completeness of the spectral domain generated by a bimeasure is discussed. The bimeasure is derived from a spectral representation of a given process of weak class (C). In particular by an example it is shown that the spectral domain of a weak class (C) process is not necessarily...

We construct a.s. nonlinear regression representations of general stochastic processes . As a consequence we obtain in particular special regression representations of Markov chains and of certain m-dependent sequences. For m-dependent sequences we obtain a constructive method to check, whether...

We consider optimal stopping of independent sequences. Assuming that the corresponding imbedded planar point processes converge to a Poisson process we introduce some additional conditions which allow to approximate the optimal stopping problem of the discrete time sequence by the optimal...

A characterization is proved for random variables which are optimal couplings w.r.t. a general function c. It turns out that on very general probability spaces optimal couplings can be characterized by generalized subgradients of c-convex functions. An interesting application of optimal...

In this paper a quantitative approximation result is obtained for a general class of function nets which is of interest in functional estimation. Specific applications are given to approximation by neural nets, radial basis function nets, and wavelet nets. For the proof we combine the empirical...