arXiv subjects

Sergey Tikhomirov

Publications and source records attributed to Sergey Tikhomirov.

30 records · Page 2Linked to original sources

arXiv2013

Systems of reaction-diffusion equations with spatially distributed hysteresis

We study systems of reaction-diffusion equations with discontinuous spatially distributed hysteresis in the right-hand side. The input of hysteresis is given by a vector-valued function of space and time. Such systems describe hysteretic interaction of non-diffusive (bacteria, cells, etc.) and diffusive (nutrient, proteins, etc.) substances leading to formation of spatial patterns. We provide sufficient conditions under which the problem is well posed in spite of the discontinuity of hysteresis. These conditions are formulated in terms of geometry of manifolds defining hysteresis thresholds and the graph of initial data.

math.AP↗

arXiv2013

Shadowing for actions of some finitely generated groups

We introduce a notion of shadowing property for actions of finitely generated groups and study its basic properties. We formulate and prove a shadowing lemma for actions of nilpotent groups. We construct an example of a faithful linear action of a solvable Baumslag-Solitar group and show that the shadowing property depends on quantitative characteristics of hyperbolicity. Finally we show that any linear action of a non-abelian free group does not have the shadowing property.

math.DS↗

arXiv2012

Reaction-diffusion equations with spatially distributed hysteresis

The paper deals with reaction-diffusion equations involving a hysteretic discontinuity in the source term, which is defined at each spatial point. In particular, such problems describe chemical reactions and biological processes in which diffusive and nondiffusive substances interact according to hysteresis law. We find sufficient conditions that guarantee the existence and uniqueness of solutions as well as their continuous dependence on initial data.

math.AP↗

arXiv2012

Uniqueness of transverse solutions for reaction-diffusion equations with spatially distributed hysteresis

The paper deals with reaction-diffusion equations involving a hysteretic discontinuity in the source term, which is defined at each spatial point. Such problems describe biological processes and chemical reactions in which diffusive and nondiffusive substances interact according to hysteresis law. Under the assumption that the initial data are spatially transverse, we prove a theorem on the uniqueness of solutions. The theorem covers the case of non-Lipschitz hysteresis branches arising in the theory of slow-fast systems.

math.AP↗

arXiv2012

Partial hyperbolicity and central shadowing

We study shadowing property for a partially hyperbolic diffeomorphism $f$. It is proved that if $f$ is dynamically coherent then any pseudotrajectory can be shadowed by a pseudotrajectory with "jumps" along the central foliation. The proof is based on the Tikhonov-Shauder fixed point theorem.

math.DS↗

arXiv2011

Lipschitz Shadowing for Flows

Let $ϕ$ be the flow generated by a smooth vector field $X$ on a smooth closed manifold. We show that the Lipschitz shadowing property of $ϕ$ is equivalent to the structural stability of $X$ and that the Lipschitz periodic shadowing property of $ϕ$ is equivalent to the $Ω$-stability of $X$.

math.DS↗

arXiv2010

Symmetric periodic solutions of parabolic problems with hysteresis

We consider the heat equation in a multidimensional domain with nonlocal hysteresis feedback control in a boundary condition. Thermostat is our prototype model. We construct all periodic solutions with exactly two switching on the period and study their stability. Coexistence of several periodic solutions with different stability properties is proved to be possible. A mechanism of appearance and disappearance of periodic solutions is investigated.

math.AP↗

arXiv2010

Lipschitz shadowing implies structural stability

We show that the Lipschitz shadowing property of a diffeomorphism is equivalent to structural stability. As a corollary, we show that an expansive diffeomorphism having the Lipschitz shadowing property is Anosov.

math.DS↗

arXiv2010

Periodic shadowing and $Ω$-stability

We show that the following three properties of a diffeomorphism $f$ of a smooth closed manifold are equivalent: (i) $f$ belongs to the $C^1$-interior of the set of diffeomorphisms having periodic shadowing property; (ii) $f$ has Lipschitz periodic shadowing property; (iii) $f$ is $Ω$-stable.

math.DS↗

arXiv2010

Vector Fields with the Oriented Shadowing Property

We give a description of the $\Cone$-interior ($\Int^1(\OrientSh)$) of the set of smooth vector fields on a smooth closed manifold that have the oriented shadowing property. A special class $\Bb$ of vector fields that are not structurally stable is introduced. It is shown that the set $\Int^1(\OrientSh\setminus\Bb)$ coincides with the set of structurally stable vector fields. An example of a field of the class $\Bb$ belonging to $\Int^1(\OrientSh)$ is given. Bibliography: 18 titles.

math.DS↗

arXiv2010

Sets of vector fields with various properties of shadowing of pseudotra-jectories

We study the structure of $C^1$-interiors of sets of smooth vector fields with various properties of shadowing of pseudotrajectories. It is shown for which classes of reparametrizations of shadowing trajectories the corresponding interiors consist of structurally stable fields.

math.DS↗

arXiv2010

Interiors of sets of vector fields with shadowing corresponding to certain classes of reparameterizations

We study $C^1$-interiors of sets of vector fields with various shadowing properties. For the case of Lipschitz shadowing property the $C^1$-interior equals the set of structurally stable vector fields. If the dimension of the manifold does not exceed 3 a similar result holds for the oriented shadowing property.

math.DS↗