Center problem for a class of degenerate quartic systems

This paper, using pseudo-division algorithm, introduces a method for computing resonant focus numbers of a class of complex polynomial differential systems, establishes the necessary and sufficient conditions for existence of a center for a class of complex quartic systems with a degenerate resonant singular point

Thomas decompositions of parametric nonlinear control systems

This paper presents an algorithmic method to study structural properties of nonlinear control systems in dependence of parameters. The result consists of a description of parameter configurations which cause different control-theoretic behaviour of the system (in terms of observability, flatness, etc.). The constructive symbolic method is based on the differential Thomas decomposition into disjoint simple systems, in particular its elimination properties

Multiplicity Preserving Triangular Set Decomposition of Two Polynomials

In this paper, a multiplicity preserving triangular set decomposition algorithm is proposed for a system of two polynomials. The algorithm decomposes the variety defined by the polynomial system into unmixed components represented by triangular sets, which may have negative multiplicities. In the bivariate case, we give a complete algorithm to decompose the system into multiplicity preserving triangular sets with positive multiplicities. We also analyze the complexity of the algorithm in the bivariate case. We implement our algorithm and show the effectiveness of the method with extensive experiments.Comment: 18 page

Embodied pollution in Spanish household consumption: a disaggregate analysis

In this paper we apply an environmentally extended input-output model to analyse a specific issue related to the Environmental Kuznets Curve hypothesis. The purpose is to study whether the consumption structure ofwealthier households has a positive effect on the reduction of environmental pressures. Combining information from different databases, we analysed the impact of the consumption of Spanish households in 2000 on atmospheric pollution. We considered nine gases: the six greenhouse gases (CO2, CH4, N2O, SF6, HFCs, and PFCs) and three other gases (SO2, NOx, and NH3). We classified households by quintiles of per capita expenditure and equivalent expenditure. We found that there was a positive and very high relationship between the level of expenditure and direct and indirect emissions generated by household consumption; however, the emission intensities tended to decrease with the expenditure level for the various atmospheric pollutants, with the exception of SF6, HFCs and PFCs.input-output analysis, atmospheric pollution, environmental, spain, consumption patterns, kuznets curve