The purpose of this note is to show a new characterization of the IFR and DFR aging notions by means of the dispersive order. Our result extends results of Mailhot (1987) and of Belzunce, Candel and Ruiz (1995). Our method of proof can also be extended to handle comparisons of "past lives", that...

The problem of the preservation of non-parametric life distributions classes under addition of life lengths has been extensively studied in literature. In literature, however, independence among the random life lengths is often assumed. Here we show that for the HNBUE life distributions class...

In this note we provide new results of interest in the portfolio choice problem when the risky opportunities are correlated: for a general vector (X <Subscript>1</Subscript>, X <Subscript>2</Subscript>,..., X <Subscript> n </Subscript>) of risky opportunities we give new conditions for stochastic comparison among different portfolios choices and new necessary and...</subscript></subscript></subscript>

A class of generalized bivariate Marshall-Olkin distributions, which includes as special cases the Marshall-Olkin bivariate exponential distribution and the Marshall-Olkin type distribution due to Muliere and Scarsini (1987) [19] are examined in this paper. Stochastic comparison results are...

Different sufficient conditions for stochastic comparisons between random vectors have been described in the literature. In particular, conditions for the comparison of random vectors having the same copula, i.e., the same dependence structure, may be found in Müller and Scarsini (2001). Here...

We consider the problem of stochastic comparison of general Garch-like processes, for different parameters and different distributions of the innovations. We identify several stochastic orders that are propagated from the innovations to the Garch process itself, and discuss their...

In this paper, we introduce a new multivariate stochastic order that compares random vectors in a direction which is determined by a unit vector, generalizing the previous upper and lower orthant orders. The main properties of this new order, together with its relationships with other...