245 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
Neue Cassidinen aus China (Coleoptera: Chrysomelidae).
No full textIn der vorliegenden Arbeit werden die Ergebnisse der Bearbeitung chinesischer Cassidinen aus der Sammlung des Verfassers mitgeteilt. Es werden drei neue Arten und zwei neue Unterarten beschrieben, ferner werden zwei für China noch nicht bekannte Arten angeführt und das Areal einiger Formen präzisiert. Die Typen und Paratypen der neu beschriebenen Arten, bzw. Unterarten, befinden sich in der Sammlung des Zoologischen Institutes der Akademie der Wissenschaften der SU und in der Sammlung des Autors.Nomenklatorische Handlungengresitti [sic!] Medvedev, 1957 (Basiprionota), spec. n.mongolensis Medvedev, 1957 (Cassida prasina), sspec. n.hincksi Medvedev, 1957 (Cassioa Mionycha), spec. n.gansuica Medvedev, 1957 (Glyphocassis spilota), sspec. n.pygmaea Medvedev, 1957 (Thlaspida), spec. n.The results of the treatment of Chinese Cassidinae from the author\u27s collection are discussed. There are described 3 new species, 2 new subspecies, and mentioned species new to China. Types and Paratypes in the collection of the Zool. Inst. Acad. Sei. USSR and in the author\u27s collection.Nomenclatural Actsgresitti [sic!] Medvedev, 1957 (Basiprionota), spec. n.mongolensis Medvedev, 1957 (Cassida prasina), sspec. n.hincksi Medvedev, 1957 (Cassioa Mionycha), spec. n.gansuica Medvedev, 1957 (Glyphocassis spilota), sspec. n.pygmaea Medvedev, 1957 (Thlaspida), spec. n
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
Corrigendum to ‘Cu-substituted La2NiO4+δ as oxygen electrodes for protonic ceramic electrochemical cells’ [Ceram. Int.](S0272884219312362)(10.1016/j.ceramint.2019.05.127)
No full textThe authors regret that in the published version of this article the middle initial of the author Dmitry Medvedev was shown as ‘M’ instead of ‘A’. The author name is shown correctly as Dmitry A. Medvedev above. The authors would like to apologise for any inconvenience caused. © 2019 Elsevier Ltd and Techna Group S.r.l
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