615 research outputs found

    The Liouville-type theorem for integrable Hamiltonian systems with incomplete flows

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    For integrable Hamiltonian systems with two degrees of freedom whose Hamiltonian vector fields have incomplete flows, an analogue of the Liouville theorem is established. A canonical Liouville fibration is defined by means of an "exact" 2-parameter family of flat polygons equipped with certain pairing of sides. For the integrable Hamiltonian systems given by the vector field v=(f/w,f/z)v=(-\partial f/\partial w, \partial f/\partial z) on C2{\mathbb C}^2 where f=f(z,w)f=f(z,w) is a complex polynomial in 2 variables, geometric properties of Liouville fibrations are described.Comment: 6 page

    Connected components of spaces of Morse functions with fixed critical points

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    Let MM be a smooth closed orientable surface and F=Fp,q,rF=F_{p,q,r} be the space of Morse functions on MM having exactly pp critical points of local minima, q1q\ge1 saddle critical points, and rr critical points of local maxima, moreover all the points are fixed. Let FfF_f be the connected component of a function fFf\in F in FF. By means of the winding number introduced by Reinhart (1960), a surjection π0(F)Zp+r1\pi_0(F)\to{\mathbb Z}^{p+r-1} is constructed. In particular, π0(F)=|\pi_0(F)|=\infty, and the Dehn twist about the boundary of any disk containing exactly two critical points, exactly one of which is a saddle point, does not preserve FfF_f. Let D\mathscr D be the group of orientation preserving diffeomorphisms of MM leaving fixed the critical points, D0{\mathscr D}^0 be the connected component of idM{\rm id}_M in D\mathscr D, and DfD{\mathscr D}_f\subset{\mathscr D} the set of diffeomorphisms preserving FfF_f. Let Hf{\mathscr H}_f be the subgroup of Df{\mathscr D}_f generated by D0{\mathscr D}^0 and all diffeomorphisms hDh\in{\mathscr D} which preserve some functions f1Fff_1\in F_f, and let Hfabs{\mathscr H}_f^{\rm abs} be its subgroup generated D0{\mathscr D}^0 and the Dehn twists about the components of level curves of functions f1Fff_1\in F_f. We prove that HfabsDf{\mathscr H}_f^{\rm abs}\subsetneq{\mathscr D}_f if q2q\ge2, and construct an epimorphism Df/HfabsZ2q1{\mathscr D}_f/{\mathscr H}_f^{\rm abs}\to{\mathbb Z}_2^{q-1}, by means of the winding number. A finite polyhedral complex K=Kp,q,rK=K_{p,q,r} associated to the space FF is defined. An epimorphism μ:π1(K)Df/Hf\mu:\pi_1(K)\to{\mathscr D}_f/{\mathscr H}_f and finite generating sets for the groups Df/D0{\mathscr D}_f/{\mathscr D}^0 and Df/Hf{\mathscr D}_f/{\mathscr H}_f in terms of the 2-skeleton of the complex KK are constructed.Comment: 12 pages with 2 figures, in Russian, to be published in Vestnik Moskov. Univ., a typo in theorem 1 is correcte

    Efficiency of Developing Renewable Energy Market in Russia

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    The goal of this study is to systematize and provide a quantitative and qualitative assessment of potential positive economic and non-economic effects of the implementation of a new mechanism for supporting renewable energy in Russia. It should result in achieving the national medium-term objective to increase the share of renewable energy in the wholesale electricity and capacity market to 2.5 % by 2024. The introduction examines the mechanism for supporting the generators of renewable energy by capacity charge in the wholesale electricity and capacity market. It is assumed that the main positive effects from implementing this mechanism will be the replacement of hydrocarbon fuels burned for generating the electricity in traditional coal or gas power plants; improvement in the trade balance; multiplier effects from the development of RES in related industrial sectors, new value added and jobs in the sectors producing the generating and auxiliary equipment for generators; reduction of carbon dioxide emissions; decrease in average prices in the wholesale electricity market; reduction of expenditure on environmental activities and measures to protect the health in the territories with traditional power plants; additional scal charges. As a result, the quantification of these effects amounts to 47.77 billion rubles in 2024. The authors rely on the experience of foreign countries, expert estimates, forecasts by the Russian Ministry of Energy and the Ministry of Economic Development, research by the Russian Energy Agency, International Energy Agency, International Renewable Energy Agency, Community for Renewable Energy Policy in the 21st Century (REN21), statistics of Russian Federal State Statistics Service.The article has been supported by the Russian Foundation for Basic Research as part of the project 14–06–00075 “National Economic and Environmental Security: Threats, Effects, and Scenario for Interaction of Economy and Environment.

    Topology of the spaces of Morse functions on surfaces

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    Let MM be a smooth closed orientable surface, and let FF be the space of Morse functions on MM such that at least χ(M)+1\chi(M)+1 critical points of each function of FF are labeled by different labels (enumerated). Endow the space FF with CC^\infty-topology. We prove the homotopy equivalence FR×M~F\sim R\times{\widetilde{\cal M}} where RR is one of the manifolds RP3{\mathbb R}P^3, S1×S1S^1\times S^1 and the point in dependence on the sign of χ(M)\chi(M), and M~{\widetilde{\cal M}} is the universal moduli space of framed Morse functions, which is a smooth stratified manifold. Morse inequalities for the Betti numbers of the space FF are obtained.Comment: 15 pages, in Russia
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