Evolution of Sets Systems and Homotopy Groups of Spheres

Симеон Т. Стефанов, Велика И. Драгиева - В работата е изследвана еволюцията на системи от множества върху n-мерната евклидова сфера S^n. Установена е връзката на такива системи с хомотопичните групи на сферите. Получени са някои комбинаторни приложения за многостени.

On the homotopy groups of the self-equivalences of linear spheres

Peer reviewed

On the homotopy groups of the self-equivalences of linear spheres

Peer reviewed

Gas-solid coexistence of adhesive spheres

In this note, the authors investigate whether the gas-liquid critical point can remain stable with respect to solidification for narrow attractive interactions down to the Baxter limit. Using a crude cell theory, the authors estimate the necessary conditions for this to be true. Possible realizations are briefly discussed.

Geodesically reversible Finsler 2-spheres of constant curvature

A Finsler space is said to be geodesically reversible if each oriented geodesic can be reparametrized as a geodesic with the reverse orientation. A reversible Finsler space is geodesically reversible, but the converse need not be true. In this note, building on recent work of LeBrun and Mason, it is shown that a geodesically reversible Finsler metric of constant flag curvature on the 2-sphere is necessarily projectively flat. As a corollary, using a previous result of the author, it is shown that a reversible Finsler metric of constant flag curvature on the 2-sphere is necessarily a Riemannian metric of constant Gauss curvature, thus settling a long- standing problem in Finsler geometry.

The Herglotz variational problem on spheres and its optimal control approach

The main goal of this paper is to extend the generalized variational problem of Herglotz type to the more general context of the Euclidean sphere S^n. Motivated by classical results on Euclidean spaces, we derive the generalized Euler-Lagrange equation for the corresponding variational problem defined on the Riemannian manifold S^n. Moreover, the problem is formulated from an optimal control point of view and it is proved that the Euler-Lagrange equation can be obtained from the Hamiltonian equations. It is also highlighted the geodesic problem on spheres as a particular case of the generalized Herglotz problem.

On homotopy spheres of low dimension

Let M be a smooth compact manifold homotopy equivalent to the 4-sphere S^4. Then M x R^1 is homeomorphism co S^4 x R^1.

Spheres of Influence: A Few Reflections on the Concept

In the frame of the Ukrainian crisis the question of spheres of influence has returned to political discourse. This may be an awkward subject, but what if we only deny the existence of such power constellations as spheres of influence? Do spheres of influence exist, or are they relics of history, and mere rhetoric? And if they exist, where can we find them? The hypothesis in this article is that instead of being a tangible reality, spheres of influence are obscure and contested political constructions, which nevertheless can have an impact on political behaviour. To demonstrate this, the article will first introduce a few examples of the current use of the concept. Secondly, a few remarks follow concerning the different IR schools of thought, and conceptual history as a method. Next, the article turns to discussing a few dictionaries and the empirical material for the present inquiry, which consists of recent textbooks, i.e. the current political science curriculum in one particular university, at the University of Tampere, Finland. More empirical cases deal with the division of Africa, the post-WWII situation, and the Hungarian revolution of 1956.

Three Spheres of Classification Research: Emergence, Encyclopedism, and Ecology

Three paths of interdisciplinary work shape the future of classification research.emergence, encyclopedism, and ecology. Each of these, in method, approach, and in substantive inquiry outline both the boundaries and the intersections of the many fields that contribute to our overall understanding of classification research. This paper outlines some high level claims of this work, ties it to current research and offers some theoretical applications of these paths.

ABSTINENCE AND ALCOHOL CONSUMPTION AMONG STUDENTS: THE INFLUENCE OF PERSONAL, FAMILY AND SOCIO-CULTURAL SPHERES

Introduction: Among young people, regular or alcohol abuse seems to ally with individual factors, which congregate to other generators behaviors health risk, in social environment, including family and school. The consumption of alcoholic beverages in the younger age groups, according to the World Development Report goes beyond 60%. In the Portuguese case, the Alentejo is the region that recorded higher consumption among schoolchildren. Objectives: This study aims to know the personal inluences of family, of belonging to the group and the school environment, on the withdrawal and consumption habits among young people. Methods: A qualitative nature of research, using comprehensive semi-structured interviews. The study was developed in a school district of Evora, Portugal. The sample consists of ten students from the 8th school grade, ive non-consumers-ive consumers aged between 13 and 15 years old. Results: The trial takes place between 12 and 14 years old as a result of curiosity, explicit or tacit motivation, “give style”, the environment, entertainment and observing behavior. Among the effects of intake indicated as motivators consumption highlight the joy of reaching states and willingness. Family members tend to encourage moderate drinking on festive occasions. family models exaggerated consumption repudiate ingestion. The elements of the group of belonging tend to motivate explicitly, the intake among consumers students. The school promotes initiatives on the theme, punctually. Conclusions: The consumption of alcohol among young people suffer the personal, family and belonging group inluences. The initiatives in school tend to have no effect.

O esporte paraolímpico no Brasil : abordagem da sociologia do esporte de Pierre Bourdieu

Universidade Estadual de Campinas . Faculdade de Educação Física