362 research outputs found
Geometry of third order ODE systems
No full textWe compute cohomology spaces of Lie algebras that describe
differential invariants of third order ordinary differential equations. We prove
that the algebra of all differential invariants is generated by 2 tensorial
invariants of order 2, one invariant of order 3 and one invariant of order 4.
The main computational tool is a Serre-Hochschild spectral sequence and
the representation theory of semisimple Lie algebras. We compute differential
invariants up to degree 2 as application
Third Order ODEs Systems and Its Characteristic Connections
No full textWe compute the characteristic Cartan connection associated with a system of third order ODEs. Our connection is different from Tanaka normal one, but still is uniquely associated with the system of third order ODEs. This allows us to find all fundamental invariants of a system of third order ODEs and, in particular, determine when a system of third order ODEs is trivializable. As application differential invariants of equations on circles in R^n are computed
FUNDAMENTAL INVARIANTS OF SYSTEMS OF ODES OF HIGHER ORDER
No full textWe find the complete set of fundamental invariants for systems of ordinary differential equations of order >= 4 under the group of point transformations generalizing similar results for contact invariants of a single ODE and point invariants of systems of the second and the third order. It turns out that starting from systems of order (k + 1) >= 4, the complete set of fundamental invariants is formed by k generalized Wilczynski invariants coming from the linearized system and an additional invariant of degree 2
3-dimensional left-invariant sub-Lorentzian contact structures
No full textWe provide a classification of ts-invariant sub-Lorentzian structures on 3 dimensional contact Lie groups. Our approach is based on invariants arising form the construction of a normal Cartan connection. © 2016 Elsevier B.V
Russia and its 'New Security Architecture' in Europe: A Critical Examination of the Concept. CEPS Working Document No. 310, 5 February 2009
No full textOne of the most important effects of Russia’s war against Georgia in August 2008 was a new set of approaches to the future of European security being actively promoted by Dmitry Medvedev and Foreign Minister Sergey Lavrov. According to their interpretation, the Georgian war was not a particular incident (an exception) but a structural event, a landmark comparable to Russia’s own 'September 11' to be symbolised as a 'moment of truth'. This Working Document looks at Russia’s critique of the existing security architecture and its search for a new one
Alexandr Berndorf - author of my region
No full textTéma této bakalářské práce nese název Alexandr Berndorf autor mého regionu. Práce je rozdělena do několika částí. První kapitola se zabývá životem tohoto spisovatele a vychází z autorova vlastnoručně psaného životopisu a životopisné studie napsané Zdeňkem Papešem. Dále si práce všímá části beletristické tvorby Alexandra Berndorfa a jeho vztahu k rodnému kraji. Hlavním cílem práce je představit tohoto dnes již nepříliš známého autora a připomenout jeho přínos nepomuckému regionu.ObhájenoThe topic of this Bachelor thesis is Alexandr Berndorf an author from my native region. The work itself is divided into several parts. The first chapter maps the life of this writer and is based on his own autobiography as well as a biographic study written by Zdeněk Papeš. Furthermore, the thesis focuses on Berndorf's prose and his relationship with his birth land. Overall, its main goal is to introduce this almost forgotten author and to remind everybody of his contribution to the Nepomuk region
Blogging for the Sake of the President
No full textMany western researchers have hailed blogs of politicians as new, interactive, and ‘inherently democratic’ tools of political communication. Yet, as this chapter illustrates, blogs can be of comparatively even greater appeal to politicians in semi-authoritarian political contexts: In Russia, 29 out of 83 regional leaders (roughly 35 %) were keeping a weblog in May 2010. This chapter accomplishes a comprehensive content analysis of all governors’ blogs and, subsequently, fleshes out a typology of three characteristic types. In conclusion, it is argued that politicians’ blogs are playing a far greater role in generating legitimacy for the Russian political system than they do in democracies, because the semi-authoritarian Russian system lacks other mechanisms which generate (input) legitimacy in developed democracies, such as highly competitive elections
Alexandr Sukorov’s passıng world
No full textThe author of this article concentrates his attention on the films directed by Alexandr Sokurov, a distinguished contemporary Russian filmmaker. Syska describes the political and aesthetical background of Sokurov’s works, underlying their key motifs: melancholy, nostalgia, reminiscences, decay of physical world, memories and time. The author mentions autobiographical components of Sokurov’s screenplays, describes his childhood defined by eternal displacement of his family, as well as the adultness - with political troubles caused by anti-communism attitude and close friendship with Tarkovsky. Syska analyzes the literary context of Sokurov’s films, cultural paradigm, religious character of film narration and theme of carnal sacrifice. All of them allow him to describe the human as someone who is deeply devoted to the internal world of memories, nostalgia, passing time and intimate relationship with dying parents
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