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Classification of Morse–Smale diffeomorphisms with a finite set of heteroclinic orbits on surfaces
Moscow Mathematical Journal. 2023. Vol. 23. No. 4. P. 571–590.
Morozov A., Pochinka O.
In this paper, we consider orientation-preserving Morse-Smale diffeomorphisms on orientable closed surfaces. Such diffeomorphisms can have infinitely many heteroclinic orbits, which makes their topological classification very difficult. In fact, even in the case of a finite number of heteroclinic orbits, there are no exhaustive classification results. The main problem is that for all currently known complete topological invariants of such systems, the implementation is not described. In this paper, we present a complete topological classification of Morse-Smale diffeomorphisms with a finite number of heteroclinic orbits on surfaces, including a realization.
Denis Seliutskii, Russian Journal of Mathematical Physics 2025 Vol. 32 No. 2 P. 399–407
In this paper, we find an upper bound for the first Steklov eigenvalue for a surface of revolution with boundary consisting of two spheres of different radii. Moreover, we prove that, in some cases, this boundary is sharp. ...
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Жакупов О. Б., European Journal of Mathematics 2025 Vol. 11 Article 84
We provide examples of smooth three-dimensional Fano complete intersections of degree 2, 4, 6, and 8 that have absolute coregularity 0. Considering the main theorem of Avilov, Loginov, and Przyjalkowski (CNTP 18:506–577, 2024) on the remaining 101 families of smooth Fano threefolds, our result implies that each family of smooth Fano threefolds has an element of absolute ...
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Lerman L. M., Turaev D. V., Regular and Chaotic Dynamics 2026 Vol. 31 No. 3 P. 349–369
We show that bifurcations of four-dimensional symplectic diffeomorphisms with a quadratic homoclinic tangency to a saddle periodic orbit with real multipliers produce 2-elliptic periodic orbits if the tangency is not partially hyperbolic. We show that a normal form for the rescaled first-return maps near such tangency is given by a four-dimensional symplectic H´enonlike map and study bifurcations of the ...
Added: May 15, 2026
Aleskerov F. T., Yakuba V. I., Khutorskaya O. et al., Springer, 2026.
The book contains new models of bibliometric analysis based on centrality measures in network analysis, pattern analysis and stability analysis. A distinctive feature of these centrality measures is that they account for the parameters of vertices and group influence of vertices to a vertex. This reveals specific groups of publications, authors, terms, journals and affiliations ...
Added: May 15, 2026
Kuptsov P., Panyushev A., Stankevich N., Chaos 2026 Vol. 36 No. 5 Article 053138
We develop a machine-learning approach to reproduce the behavior of two versions of the van der Pol oscillator exhibiting a subcritical Andronov–Hopf bifurcation, with or without a codimension-2 Bautin point. We construct a neural-network model that functions as a recur rent map and train it on short segments of oscillator trajectories. The results show that, ...
Added: May 15, 2026
Dorovskiy A., / Series arXiv "math". 2026.
In this paper the structural stability of generic families of vector fields of the PC-HC class on the two-dimensional sphere is proved. A classification of these families up to moderate equivalence in neighborhoods of their large bifurcation supports is presented, based on such invariants as the configuration and the characteristic set. The realization lemma is proved. ...
Added: May 14, 2026
Lebedev V., Journal of Mathematical Analysis and Applications 2026 Vol. 563 No. 2 Article 130787
It is known that for every continuous real-valued
function $f$ on the circle $\mathbb T=\mathbb R/2\pi\mathbb Z$ there exists a
change of variable, i.e., a self-homeomorphism $h$ of $\mathbb T$, such that
the superposition $f\circ h$ is in the Sobolev space $W_2^{1/2}(\mathbb T)$.
We obtain new results on simultaneous improvement of functions by a single
change of variable in relation ...
Added: May 14, 2026
Blokh A., Oversteegen L., Selinger N. et al., Arnold Mathematical Journal 2025 Vol. 12 No. 1 P. 1–40
We describe a model for the boundary of the connectedness locus of the parameter space of cubic symmetric polynomials. We show that there exists a monotone continuous function from the connectedness locus to the model which is a homeomorphism if the former is locally connected. ...
Added: May 13, 2026
Petrov I., Автоматика и телемеханика 2026 № 6 С. 82–118
Системам связанных агентов и сетевому управлению посвящено большое число отечественных и зарубежных исследований. Исторически, наибольший интерес в теории управления возникал к усредняющим системам и, в частности, к задаче консенсуса. Однако сетевое взаимодействие может характеризоваться более специфическими функциями, отражающими зависимость от действий соседей по сети, что особенно явно проявляется в моделях стратегического взаимодействия на сети, которое ...
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М.: ООО «Макс Пресс», 2026.
В настоящем сборнике представлены тезисы докладов участников семинара "Интеграция основного и дополнительного физико-математического образования", проходившего 11 февраля 2026 года в ГБОУ Школа №2007 ФМШ г. москвы, а также другие публикации, посвящённые вопросам дополнительного физико-математического образования. ...
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Novikov R., V. N. Sivkin, Inverse Problems 2026 Vol. 42 No. 4 Article 045009
We consider a plane wave, a radiation solution, and the sum of these solutions (total solution) for
the Helmholtz equation in an exterior region in Rd, d ⩾ 2. In this region, we consider a hyperplane X with sufficiently large distance s from the origin in Rd. We give two-point local formulas
for approximate recovering the radiation ...
Added: May 11, 2026
Hecht M., Hofmann P., Wicaksono D. et al., IMA Journal of Numerical Analysis 2026 Vol. 00 P. 1–30
Recent advances in Bernstein—Walsh theory have extended Bernstein’s Theorem to multiple dimensions, stating that a multivariate function can be approximated with a geometric rate in a downward-closed polynomial space if and only if it is analytic in a generalized Bernstein polyellipse. To compute approximations of this class of functions—which we term Bos–Levenberg–Trefethen–(BLT) functions—we extend the ...
Added: May 11, 2026
Kelbert M., Kalimulina E. Y., Entropy 2026 Vol. 28 Article 536
We study binary hypothesis testing for i.i.d. observations under a multiplicative context
weight. For the optimal weighted total loss, defined as the sum of weighted type-I and typeII losses, we prove the logarithmic asymptotic L∗n = exp{−nDwC (P,Q) + o(n)}, n →∞, where Dw
C is the weighted Chernoff information. The single-letter form of the exponent
relies on ...
Added: May 7, 2026
N. Belousov, L. Cherepanov, Derkachov S. et al., Selecta Mathematica, New Series 2026 Vol. 32 Article 44
We prove equivalence of two integral representations for the wave functions of hyperbolic Calogero–Sutherland system. For this we study two families of Baxter operators related to hyperbolic Calogero–Sutherland and rational Ruijsenaars models; the first one as a limit from hyperbolic Ruijsenaars system, while the second one independently. Besides, computing asymptotics of integral representations and also ...
Added: May 6, 2026
Galkin V., Pochinka O., Успехи математических наук 2026 Т. 81 № 2(422) С. 71–144
Настоящая работа посвящена изучению динамики регулярных четырехмерных потоков, их топологической классификации и взаимосвязи с топологией несущего многообразия. Регулярные потоки являются топологическими аналогами потоков Морса–Смейла. Их появление мотивировано двумя фактами: 1) существованием топологических многообразий размерности 4 и выше, не имеющих гладкой структуры; 2) развитием методов топологической классификации гладких систем, использующих чисто топологические свойства этих систем и ...
Added: April 1, 2026
Pochinka O., Chilina E., Математический сборник 2026 Т. 217 № 3 С. 112–134
Работа посвящена исследованию сохраняющих ориентацию гомеоморфизмов трехмерных многообразий с неблуждающим множеством, состоящим из конечного числа двумерных аттракторов и репеллеров, каждый из которых является дизъюнктным объединением цилиндрически вложенных замкнутых поверхностей, ограничение некоторой степени на каждую из которых топологически сопряжено сохраняющему ориентацию псевдоаносовскому гомеоморфизму. Получена топологическая классификация модельных гомеоморфизмов, реализованных на каждом многообразии, допускающем гомеоморфизмы исследуемого класса. Доказано, ...
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Мартынов Т. Д., Pochinka O., Chilina E., Математика и теоретические компьютерные науки 2025 Т. 3 № 3 С. 87–109
According to J. Nielsen and H. Hang, each class of topological conjugacy of periodic homeomorphisms of orientable compact surfaces is completely described by a finite set of data called the characteristic. For a two-dimensional sphere, exhaustive classification results with the construction of linear representatives in each conjugacy class were obtained by B. Kerekyarto. For a ...
Added: October 18, 2025
Gurevich E., Математика и теоретические компьютерные науки 2025 Т. 3 № 3 С. 20–42
A topological classification of smooth, structurally stable flows on four-dimensional closed manifolds is obtained, the wandering set of which contains isolated trajectories connecting saddle equilibria (heteroclinic curves). For dimensional reasons, the heteroclinic curves of such flows belong to the intersection of invariant manifolds of saddles of adjacent Morse indices. We assume that the non-wandering set of ...
Added: October 18, 2025
Gurevich E., Saraev I., Communications in Nonlinear Science and Numerical Simulation 2026 Vol. 152 No. D Article 109301
We consider homeomorphisms with a finite and topologically hyperbolic chain-recurrent set and explore the interrelation between the structure of the chain-recurrent set and the topology of carrying manifolds of dimension n > 3. We demonstrate that the Lefschetz fixed-point theorem can be refined for this class of homeomorphisms as follows: if the (n-1)-dimensional invariant manifold ...
Added: October 4, 2025
Galkin V., Pochinka O., Математические заметки 2025 Т. 117 № 6 С. 861–878
Под регулярным топологическим потоком на замкнутом nn-многообразии понимается поток, цепно рекуррентное множество которого состоит из конечного числа топологически гиперболических неподвижных точек и периодических орбит. Такой поток называется неособым, если его цепно рекуррентное множество не содержит неподвижных точек. Топологической эквивалентности маломерных неособых потоков в предположениях различной общности посвящен целый ряд работ. Начиная с размерности 4 имеется пока незначительное число ...
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Barinova M., Osenkov E., Pochinka O., Regular and Chaotic Dynamics 2025 Vol. 30 No. 2 P. 226–253
In investigating dynamical systems with chaotic attractors, many aspects of global behavior of a flow or a diffeomorphism with such an attractor are studied by replacing a nontrivial attractor by a trivial one [1, 2, 11, 14]. Such a method allows one to reduce the original system to a regular system, for instance, of a Morse – Smale ...
Added: April 8, 2025
Eugene Osenkov, Pochinka O., Moscow Mathematical Journal 2025 Vol. 25 No. 1 P. 79–90
One of the fundamental results of three-dimensional topology is the Kneser–Milnor unique decomposition theorem. If a 3-manifold admits a Morse–Smale diffeomorphism without heteroclinic curves, the topology of the decomposition summands can be substantially refined. For orientable 3-manifolds this was done by C. Bonatti, V.Z. Grines, V.S. Medvedev and E. Pecou in 2002. In the present ...
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Elena Ya. Gurevich, Ilya A. Saraev, Regular and Chaotic Dynamics 2025 Vol. 30 No. 2 P. 254–278
S.~Smale has shown that any closed smooth manifold admits a gradient-like flow, which is a structurally stable flow with a finite non-wandering set. Polar flows are a specific type of gradient-like flows characterized by the simplest non-wandering set for the given manifold, consisting of exactly one source, one sink, and a finite number of saddle ...
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Gurevich E., Saraev I., Математические заметки 2024 Т. 116 № 1 С. 45–66
In the paper, the problem of topological classification of polar flows on closed four-dimensional manifolds whose set of saddle equilibrium states consists only of points having two-dimensional stable and unstable manifolds. It is shown that the complete topological invariant for such flows is the Kirby diagram, which is a framed link on a sphere intersecting ...
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