This paper is concerned with an insurance risk model whose claim process is described by a Lévy subordinator process. Lévy-type risk models have been the object of much research in recent years. Our purpose is to present, in the case of a subordinator, a simple and direct method for...

This paper is concerned with an insurance risk model whose claim process is described by a Lévy subordinator process. Lévy-type risk models have been the object of much research in recent years. Our purpose is to present, in the case of a subordinator, a simple and direct method for...

We obtain an exact expression of the negativity for SU(2)-invariant bipartite spin-(1,s) states via the partial time reversal method. Studies of thermal states show that the threshold temperature of entanglement may be arbitrary high when s is sufficient large, indicating that the entanglement...

We discuss the application of a new test for nonlinearity for economic time series. We apply the test for several monthly unemployment series from the developed economies. We find nonlinearities in the unemployment for most of the European economies, but not for US, UK or Japan.

This paper is concerned with an insurance risk model whose claim process is described by a Lévy subordinator process. Lévy-type risk models have been the object of much research in recent years. Our purpose is to present, in the case of a subordinator, a simple and direct method for...

Within the framework of transitive sufficient processes we investigate identifiability properties of unknown parameters. In particular we consider unbiased parameter estimators, which are shown to be closely connected to time reversal and to reverse martingales. One of the main results is that,...

Though time is a concept mostly associated with physics and philosophy, the concept of time is important to be understood in the discipline of economics. This paper attempts to highlight the importance of time in economics, particularly in knowledge economics, the discipline of economics that...