A Reinsurance Approach in a Two-Dimensional Model with Dependent Risks

We consider an insurer having two classes of insurance risks dependent through the number of claims of each risk in a given period of time. We assume that the insurer chooses a reinsurance strategy related to the first class of risk by means a proportional reinsurance contract; we also assume that the reinsurance strategy related to the second class of risk is of Excess of Loss reinsurance type. Within this paper, we study the possible optimal couples of proportional retention level and Excess of Loss retention limit

Caratterizzazione minero-petrografica delle mineralizzazioni a solfuri massivi nella zona piemontese del Colle della Borra (Val Soana, Alpi Occidentali)

This work provides the first detailed mineralogical-petrographical characterization of the massive sulphide deposit of Colle della Borra (Val Soana, Western Alps). The massive sulphide deposit is hosted within an ophiolitic sequence composed of calcschists with interlayered metabasites, micaschists, chloriteschists, quartzites and marbles, metamorphosed under eclogitic facies conditions (MODESTI, 2021). In particular, the ore deposit is interposed between Grt-Cld micaschists in the foot-wall and chloriteschists in the hanging-wall. The ore mineral association mainly comprises pyrite, chalcopyrite and pyrrhotite, along with sphalerite; the proportion of the three main ore minerals vary considerably in different specimens. The gangue minerals are dominated chlorite, followed by quartz, albite, carbonate, epidote, white mica and garnet. Thanks to a detailed micro-textural and geochemical study, supported by spot electron microprobe analyses and elemental maps of some trace elements (Co, Ni, As), a primary seafloor, hydrothermal-volcanogenic origin of the mineralization is suggested, which occurred on the Ligurian Piedmont Ocean floor and was followed by subduction and exhumation during the Alpine orogenic cycle. The primary oceanic features were largely obliterated by subsequent metamorphic recrystallization. However, colloform textures and fine-grained aggregates (2-10 µm) were recognized in some pyrites, and are considered as evidence of a primary origin. Further evidence is provided by chemical zoning in a pyrite crystal. In particular, Co zoning allows to clearly identify two generations of pyrite: a primary one (PyI), at the core of the crystal, with concentrations of Co (0.15-0.29 wt%) typical of pyrites from seafloor massive sulfide deposits; a secondary one (PyII), overgrown on the first, with much higher Co concentrations (2.13-2.49 wt%), attributable to metamorphic processes. The textural characters of the two generations of pyrite also reflect the metamorphic history: the anhedral morphology of PyI testifies the corrosion that occurred at some point during the prograde path, while the overgrowth of PyII on PyI, reflects the recrystallization processes that occurred during the subsequent retrograde/exhumation phase.ope

Dividends and Dynamic Solvency Insurance in Two-Dimensional Risk Models

In this paper we consider two-dimensional risk models where the claim counting processes of the two classes of business are assumed to be Poisson processes. We assume that the dividends are paid because of the presence of a reflecting upper barrier. Furthermore, in order to avoid ruin, we consider dynamic solvency insurance contracts that depend on two different definitions of time of ruin. We present a rather general model and, under different assumptions, we obtain the equations fulfilled by the discounted dividend payments and by the net single premium of dynamic solvency insurance. We also derive some boundary conditions and provide explicit solutions for some special cases