An Inventory Model for Deteriorating Items and Stock-dependent Consumption Rate

An order-level inventory model is developed for deteriorating items with uniform rate of production and stock-dependent demand. Shortages are allowed, and excess demand is backlogged. Results are illustrated with numerical examples.

     

The Gaussian cotype of operators fromC(K)

We show that the canonical embeddingC(K) →L _Φ(μ) has Gaussian cotypep, where μ is a Radon probability measure onK, and Φ is an Orlicz function equivalent tot ^p(logt) ^p/2 for larget.     

Simultaneous best approximation by three polynomials

Let [a, b] be any interval and let p₀, p₁, p_k be any three polynomials of degrees 0, 1, k, respectively, where k 2. A set of necessary and sufficient conditions for the existence of an f in C[a, b] such that p_i is the best approximation to f from the space of all polynomials of degree less than or equal to i, for all i = 0, 1, k, is given.     

Optimal Investment in a Levy Market

In this paper we consider the optimal investment problem in a market where the stock price process is modeled by a geometric Levy process (taking into account jumps). Except for the geometric Brownian model and the geometric Poissonian model, the resulting models are incomplete and there are many equivalent martingale measures. However, the model can be completed by the so-called power-jump assets. By doing this we allow investment in these new assets and we can try to maximize the expected utility of these portfolios. As particular cases we obtain the optimal portfolios based in stocks and bonds, showing that the new assets are superfluous for certain martingale measures that depend on the utility function we use.     

Ag-induced atomic structures on the Si(110) surface

We report the results of STM investigation of the initial stage of Ag adsorption on an Si(110) surface. At 0.21 ML Ag coverage, the size and orientation of the unit cell correspond to the parameters of a 16 × 2 unit cell of clean Si(110) surface. With increasing of the Ag coverage up to 0.42 ML, the type of surface reconstruction changes to a 4 × 1-Si(110)-Ag structure. The text was submitted by the authors in English.     

Synthesis and fungicidal activity of S-amino derivatives of O-alkyldithiocarbonic acids

S-Amino derivatives of O-alkyldithiocarbonic acid were prepared by oxidative condensation of certain alkaloids with sodium xanthates. Some of the compounds synthesized exhibit fungicidal activity.