Given a prime p and a natural number n, we provide simple divisibility criterions that determine whether all solvable group of order n have a nontrivial normal psubgroup, or there is exactly one group of order n without nontrivial normal psubgroups.

Most works on Web services has focused on discovery, composition and selection processes of these kinds of services. Other few works were interested in how to represent Web services search queries. However, these queries cannot be processed by ensuring a high level of performance without being adequately represented first. To this end, different query languages were designed. Even so, in the ab...

The problem of optimal portfolio selection has attracted a great attention in the finance and optimization field. The future stock price should be predicted in an acceptable precision, and a suitable model and criterion for risk and the expected return of the stock portfolio should be proposed in order to solve the optimization problem. In this paper, two new criterions for the risk of stock pr...

The paper contains several regularity results and blow-up criterions for a surface growth model, which seems to have similar properties to the 3D Navier-Stokes, although it is a scalar equation. As a starting point we focus on energy methods and Lyapunov-functionals.

This paper presents the features of the Worldwide for Microwave Interoperability Access (WiMAX) technology and pretends to establish some valid criterions for future trends of possible applications of WiMAX. A discussion is given by comparing Wireless Fidelity (Wi-Fi) and WiMAX. Several references have been included at the end of the article for those willing to know in detail about certain spe...

In the present article the syntactic approach to construction of generic models generalizing known semantic one is described. It is established a sufficient condition of homogeneity of generic model.It is shown that at the syntactic approach any countable homogeneous model is generic. Criterions and a sufficient condition of saturation of generic models formed at the syntactic way of its constr...