Search Results

You are looking at 1 - 10 of 115 items for

  • Author or Editor: J. Lopez x
  • Refine by Access: All Content x
Clear All Modify Search

Abstract  

We obtain inequalities for the weighted approximation error of Baskakov type operators and their derivatives. Such inequalities are valid for functions of polynomial growth and are expressed in terms of weighted moduli of continuity.

Restricted access

We are immersed in a knowledge society that calls for indicators to go beyond economic factors to measure the development of a country. In this paper we use an adapted microeconomic model that determines the value of a country’s intellectual capital. For this, we consider intangibles such as human development, economic structure, international trade, foreign image and innovation. This measurement of intellectual capital is divided into human and structural capital and is used to analyse the relationship between these capitals and the economic development of the 27 countries in the European Union (EU27). The results show that when we consider aspects other than economic variables, the differences between countries are larger. Moreover, there is an inverse relationship between the management of intangibles and economic growth, which is why the former progresses after the latter have occurred.

Restricted access

IfA is a σ-algebra on setX, thenl 0 (X,A) is a barrelled space of class χ0. IfA is an algebra, there are conditions which imply thatl 0 (X,A) is suprabarelled. Here, wheneverA is an algebra, we give conditions forl 0 (X,A) to be not barrelled which are related with the existence of non-trivial convergent sequences.

Restricted access

Abstract  

A conjecture by Agronsky and Ceder [3], stating that a continuum is an orbit enclosing ω-limit set of a continuous map from the k-dimensional cube I k into itself if and only if it is arcwise connected, is disproved in both directions. Our main result is a general theorem allowing a construction of orbit enclosing ω-limit sets for triangular maps.

Restricted access

Abstract  

We study classes of relative injective and projective comodules and extend well-known results about projective comodules given in [7]. The existence of covers and envelopes by these classes of comodules is also studied and used to characterize the projective dimension of a coalgebra. We also compare this homological coalgebra with the very intensively studied homological algebra of the dual algebra (see [5]).

Restricted access

The preparation of Ni(CN)21.5M (M=morpholine) and the thermal study of this and NiBr23M, Nil24M and Ni(NCS)24M are described. The thermal treatment of these compounds leads to the isolation of Ni(CN)2M, Ni(CN)20.5M, NiBr22M, Nil23M, Nil21.5M, Ni(NCS)22M and Ni(NCS)2M. With the exception of NiBr22M and Ni(NCS)22M, all intermediate species are reported here for the first time. Magnetic and spectral studies have been carried out to determine the mode of coordination and stereochemistry of the complexes. The thermal study includes the determination of stability, apparent activation energy and reaction orders, and reaction enthalpies.

Restricted access

The 1 ∶ 4 complexes of cobalt (II) and manganese (II) thiocyanates with morpholine (Morph), [M(NCS)2(Morph)4] (M=Co, Mn), were prepared and studied by means of thermogravimetry, derivative thermogravimetry and differential scanning calorimetry. By thermal treatment of the above compounds, the 1∶2 and 1∶1 complexes, [M(NCS)2(Morph)2] (M=Co, Mn; n=1, 2), were formed. Magnetic data, infrared and electronic spectra and molar conductance values for the compounds are reported. All the complexes contain N-bonded morpholine and the 1∶4 complexes are suggested to have a monomericcis pseudooctahedral structure with N-bonded thiocyanate, whereas the 1∶2 and 1∶1 complexes are considered to have a six-coordinated polymeric configuration involving bridging NCS groups.

Restricted access