Abstract. In this paper, a system of Lyapunov equationsis considered in which Ai are given n × n complex matrices, Qi are unknown n × n Hermitian positive definite matrices and P, if any, is a common solution to the Lyapunov equations (A). Both sufficient and necessary and sufficient conditions are derived for the existence of such a matrix P . Examples are presented to illustrate the results.
Human environment and its development in the political and ecological context. Broad access to all kinds of information along with globalization have given the highest status of importance to the issues related to the environment and its quality. While the crises arising in the past were of class or territorial character, currently they are very often connected with the access to high quality environmental supplies. This is a new kind of risk, and that is why it also requires new political response. The environmental aspects are in the field of interest of each government; they are also included in the programs of political parties, as well as they are the subject of treaties or other international documents. However the term "environment" has become of political importance recently. The environment-becoming the subject of international cooperation and considered as a locus politicus-has caused irreversible changes in the foreign policy. Growing power of public opinion and development of civil society are one of the most important factors stimulating the process of emancipation of the term "environment". But the question arises, why they have played such an important role in the context of the environment? This article is just an attempt to analyze the relationship among the public opinion and civil society versus doctrines concerning the "environment" and ecological consciousness. Upowszechnienie dostępu do informacji i globalizacja podniosły do najwyższej rangi zagadnienia związane z problematyką środowiskową. O ile kryzysy wybuchające w przeszłości miały głównie charakter klasowy lub terytorialny, o tyle dziś wiążą się one coraz częściej z dostępem do zasobów środowiskowych. Nowy rodzaj ryzyka, jaki je wywołuje, wymaga nowej politycznej odpowiedzi. Problematyka środowiska znajduje się w agendzie każdego rządu i w programach ugrupowań politycznych. Jest przedmiotem dokumentów międzynarodowych. Jednak pojęcie to stosunkowo niedawno nabrało charakteru politycznego. Stając się przedmiotem współpracy międzynarodowej, spowodowało nieodwracalne zmiany w polityce zagranicznej. Uznane za locus politicus, zmusiło do zweryfikowania klasycznej koncepcji suwerenności.
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