?
Существенные группы изометрий некомпактных двумерных плоских лоренцевых орбифолдов
Известия высших учебных заведений. Поволжский регион. Физико-математические науки. 2019. № 1. С. 14-28.
Боголепова Е. В., Zhukova N.
Using the bundle of pseudo-orthogonal frames some canonical covering map for two-dimensional Lorentzian orbifolds is constructed and applied. The existence of such map shows that any two-dimensional Lorentzian orbifold is very good.
It is proved that there are only two (up to isomorphisms in the category of orbifolds) two-dimensional smooth noncompact orbifolds admitting complete flat Lorentzian metrics with an essential isometry group. They are the plane and the Z2 -cone. Unlike compact orbifolds, the metric can be any from the class of flat complete Lorentzian metrics. Examples are constructed.
Bogolepova E., Zhukova N., Известия высших учебных заведений. Поволжский регион. Физико-математические науки 2019 № 1 С. 14-28
Actuality and goals. Lorentzian geometry finds widespread application in physics and is radically different from Riemannian geometry. As it is known an every smooth orbifold admits a Riemannian metric. The existence of a Lorentzian metric on an orbifold imposes restrictions on its structure. The isometry group of a Lorentzian orbifold is called inessential if it acts properly, otherwise the ...
Added: December 1, 2022
Gusein-Zade S., Manuscripta Mathematica 2018 Vol. 155 No. 3-4 P. 335-353
For a germ of a quasihomogeneous function with an isolated critical point at the origin invariant with respect to an appropriate action of a finite abelian group, H. Fan, T. Jarvis, and Y. Ruan defined the so-called quantum cohomology group. It is considered as the main object of the quantum singularity theory (FJRW-theory). We define ...
Added: October 27, 2020
Gusein-Zade S., Алгебра и анализ 2021 Т. 33 № 3 С. 73-84
Indices of singular points of a vector field or of a 1-form on a smooth manifold are closely related with the Euler characteristic through the classical Poincar\'e--Hopf theorem. Generalized Euler characteristics (additive topological invariants of spaces with some additional structures) are sometimes related with corresponding analogues of indices of singular points. Earlier, there was defined ...
Added: May 2, 2021
N. I. Zhukova, E. A. Rogozhina .., Siberian Mathematical Journal 2012 Vol. 53 No. 6 P. 1037-1050
Among closed Lorentzian surfaces, only flat tori admit non-compact full isometry groups. Moreover, for every n > 2 the standard n-dimensional flat torus equipped with canonical metric has a non-compact full isometry Lie group. We show that this fails for n= 2 and classify the flat Lorentzian metrics on the torus with a non-compact full ...
Added: October 19, 2014
Gusein-Zade S., Функциональный анализ и его приложения 2018 Т. 52 № 4 С. 72-85
The Euler characteristic is the only additive topological invariant for spaces of certain sort, in particular, for manifolds with certain finiteness properties. A generalization of the notion of a manifold is the notion of a V-manifold. We discuss a universal additive topological invariant of V-manifolds, the universal Euler characteristic. It takes values in the ring ...
Added: October 27, 2020
N. I. Zhukova, Transformation Groups 2017
We prove an analog of the Lichnerowicz conjecture for compact and noncompact
Riemannian orbifolds. In particular, we prove that any compact Riemannian
orbifold of dimension n >2 with an essential connected Lie group of conformal
transformations is conformally equivalent to the canonical Riemannian orbifold which is the
quotient space of the standard n-dimensional sphere by a finite isometry group ...
Added: April 4, 2017
Bogolepova E., Zhukova N., Lobachevskii Journal of Mathematics 2021 Vol. 42 No. 14 P. 3324-3335
We prove a criterion of an Anosov action of the isometry group for compact Lorentzian 2-orbifolds. It is proved also that a non-compact complete flat Lorentzian 2-orbifold has an Anosov isometry if and only if its isometry group Lie acts improperly. The existence of chaotic behavior of such Anosov actions is investigated. It is shown ...
Added: February 3, 2022
Omelchenko A., Краско Е. С., Discrete Mathematics 2019 Vol. 342 No. 2 P. 600-614
The second part of the paper is devoted to enumeration of r-regular maps on the torus up to all its homeomorphisms (unsensed maps). We describe in detail the periodic orientation reversing homeomorphisms of the torus which turn out to be representable as glide reflections. We show that considering quotients of the torus with respect to ...
Added: September 21, 2018
Omelchenko A., Краско Е. С., Discrete Mathematics 2019 Vol. 342 No. 2 P. 584-599
The work that consists of two parts is devoted to the problem of enumerating unrooted r-regular maps on the torus up to all its symmetries. We begin with enumerating near-r- regular rooted maps on the torus, the projective plane and the Klein bottle, as well as some special kinds of maps on the sphere: near-r-regular ...
Added: September 21, 2018
Zhukova N., Moscow Mathematical Journal 2018
We introduce a category of rigid geometries on singular spaces which
are leaf spaces of foliations and are considered as leaf manifolds. We
single out a special category F_0 of leaf manifolds containing the orbifold
category as a full subcategory. Objects of F_0 may have non-Hausdorff
topology unlike the orbifolds. The topology of some objects of F_0 does
not satisfy ...
Added: April 2, 2018
Жукова Н.И., Чубаров Г.В .., Вестник ННГУ им. Н.И. Лобачвского 2012 № 5(1) С. 157-164
Введено понятие обобщённых надстроечных слоений. Дана интерпретация групп голономии этих слоений. Установлена связь с интегрируемыми связностями Эресмана. Обобщённые надстроечные слоения посредством существования специальной полной римановой метрики на , относительно которой это слоение вполне геодезическое. Доказан критерий устойчивости слоев в смысле Эресмана и Риба. ...
Added: October 14, 2014
Zhukova N., Журнал Средневолжского математического общества 2017 Т. 19 № 4 С. 33-44
For any smooth orbifold $\mathcal N$ is constructed a foliated model, which is a foliation
with an Ehresmann, the leaf space of which is the same as $\mathcal N$. We investigate
the relationship relationship between some properties of orbifold and its foliated model.
The article discusses the application to Cartan orbifolds, that is orbifolds endowed with Cartan geometry. ...
Added: February 20, 2018
N. I. Zhukova, Journal of Geometry and Physics 2018 Vol. 132 P. 146-154
We present a new method of investigation of G-structures on orbifolds.
This method is founded on the consideration of a G-structure on an
n-dimensional orbifold as the corresponding transversal
structure of an associated foliation. Using this method we prove the
existence and the uniqueness of a finite dimensional Lie group structures
on the full automorphism group of an elliptic G-structure ...
Added: April 4, 2017
Zhukova N., Уфимский математический журнал 2018 Т. 10 № 2 С. 43-56
The groups of conformal transformations of $n$-dimensional
pseudo-Riemannian orbifolds $({\mathcal N},g)$ are investigated for $n\geq 3$.
The Alekseevskii method of the investigation of the conformal transformation groups of
Riemannian manifolds is extended by us to psevdo-Riemannian orbifolds. It is shown that
a conformal pseudo-Riemannian geometry is induced on each stratum of that orbifold. Due to this,
for $k\in\{0,1\}\cup\{3,...,n-1\}$ exact estimates ...
Added: March 19, 2018
Bagaev A. V., Zhukova N., Journal of Geometry and Physics 2019 Vol. 142 P. 80-91
S.S. Chern conjectured that the Euler characteristic of every closed affine
manifold has to vanish. We present an analog of this conjecture stating that
the Euler-Satake characteristic of any compact affine orbifold is equal to zero.
We prove that Chern's conjecture is equivalent to its analog for
the Euler-Satake characteristic of compact affine orbifolds, and
orbifolds may be ineffective. This ...
Added: April 26, 2019
Zhukova N., Рогожина Е. А., Сибирский математический журнал 2012 Т. 53 № 6 С. 1292-1309
лоренцев орбифолд, лоренцева поверхность, группа изометрий, аносовский автоморфизм тора ...
Added: September 29, 2014
Kotelnikova M. V., Aistov A., Вестник Нижегородского университета им. Н.И. Лобачевского. Серия: Социальные науки 2019 Т. 55 № 3 С. 183-189
The article describes a method that allows to improve the content of disciplines of the mathematical cycle by dividing them into invariant (general) and variable parts. The invariants were identified for such disciplines as «Linear algebra», «Mathematical analysis», «Probability theory and mathematical statistics» delivered to Bachelors program students of economics at several universities. Based on ...
Added: January 28, 2020
Borzykh D., ЛЕНАНД, 2021
Книга представляет собой экспресс-курс по теории вероятностей в контексте начального курса эконометрики. В курсе в максимально доступной форме изложен тот минимум, который необходим для осознанного изучения начального курса эконометрики. Данная книга может не только помочь ликвидировать пробелы в знаниях по теории вероятностей, но и позволить в первом приближении выучить предмет «с нуля». При этом, благодаря доступности изложения и небольшому объему книги, ...
Added: February 20, 2021
В. Л. Попов, Математические заметки 2017 Т. 102 № 1 С. 72-80
Мы доказываем, что аффинно-треугольные подгруппы являются борелевскими подгруппами групп Кремоны. ...
Added: May 3, 2017
Красноярск : ИВМ СО РАН, 2013
Труды Пятой Международной конференции «Системный анализ и информационные технологии» САИТ-2013 (19–25 сентября 2013 г., г.Красноярск, Россия): ...
Added: November 18, 2013
Min Namkung, Younghun K., Scientific Reports 2018 Vol. 8 No. 1 P. 16915-1-16915-18
Sequential state discrimination is a strategy for quantum state discrimination of a sender’s quantum
states when N receivers are separately located. In this report, we propose optical designs that can
perform sequential state discrimination of two coherent states. For this purpose, we consider not
only binary phase-shifting-key (BPSK) signals but also general coherent states, with arbitrary prior
probabilities. Since ...
Added: November 16, 2020
Grines V., Gurevich E., Pochinka O., Russian Mathematical Surveys 2017 Vol. 71 No. 6 P. 1146-1148
In the paper a Palis problem on finding sufficient conditions on embedding of Morse-Smale diffeomorphisms in topological flow is discussed. ...
Added: May 17, 2017
Okounkov A., Aganagic M., Moscow Mathematical Journal 2017 Vol. 17 No. 4 P. 565-600
We associate an explicit equivalent descendent insertion to any relative insertion in quantum K-theory of Nakajima varieties.
This also serves as an explicit formula for off-shell Bethe eigenfunctions for general quantum loop algebras associated to quivers and gives the general integral solution to the corresponding quantum Knizhnik Zamolodchikov and dynamical q-difference equations. ...
Added: October 25, 2018
Danilov B.R., Moscow University Computational Mathematics and Cybernetics 2013 Vol. 37 No. 4 P. 180-188
The article investigates a model of delays in a network of functional elements (a gate network) in an arbitrary finite complete basis B, where basis elements delays are arbitrary positive real numbers that are specified for each input and each set of boolean variables supplied on the other inputs. Asymptotic bounds of the form τ ...
Added: December 2, 2019