for Journals by Title or ISSN for Articles by Keywords help
 Subjects -> MATHEMATICS (Total: 864 journals)     - APPLIED MATHEMATICS (68 journals)    - GEOMETRY AND TOPOLOGY (19 journals)    - MATHEMATICS (643 journals)    - MATHEMATICS (GENERAL) (40 journals)    - NUMERICAL ANALYSIS (19 journals)    - PROBABILITIES AND MATH STATISTICS (75 journals) MATHEMATICS (643 journals)                  1 2 3 4 | Last

1 2 3 4 | Last

 Bulletin of the Brazilian Mathematical Society, New Series   [SJR: 0.436]   [H-I: 19]   [0 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1678-7544 - ISSN (Online) 1678-7714    Published by Springer-Verlag  [2335 journals]
• Sectional Anosov Flows: Existence of Venice Masks with Two Singularities
• Authors: Andrés M. López Barragán; Henry M. S. Sánchez
Pages: 1 - 18
Abstract: We show the existence of Venice masks (i.e. nontransitive sectional Anosov flows with dense periodic orbits, Bautista and Morales http://preprint.impa.br/Shadows/SERIE_D/2011/86.html; Bautista et al. Discr Contin Dyn Syst 19(4):761, 2007; Morales and Pacífico Pac J Math 216(2):327–342, 2004, Morales et al. Pac J Math 229(1):223–232, 2007) containing two equilibria on certain compact 3-manifolds. Indeed, we present two type of examples in which the homoclinic classes composing their maximal invariant set intersect in a very different way.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0015-7
Issue No: Vol. 48, No. 1 (2017)

• Compact Invariant Sets for Global Holomorhic Foliations
• Authors: Arturo Fernández-Pérez; Rogério Mol; Rudy Rosas
Pages: 19 - 28
Abstract: We study compact invariant sets for holomorphic foliations on Stein manifold. As application, we show some dynamical properties concerning minimal sets (with singularities) of foliations and real analytic Levi-flat hypersurfaces in projective spaces.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0012-x
Issue No: Vol. 48, No. 1 (2017)

• Stability Of Branched Pull-Back Projective Foliations
• Authors: W. Costa e Silva
Pages: 29 - 44
Abstract: We present new irreducible components of the space of codimension one holomorphic foliations on $$\mathbb P^{n}$$ , $$n\ge 3$$ . They are associated to pull-back by branched rational maps of foliations on $$\mathbb P^2$$ that preserve invariant lines.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0007-7
Issue No: Vol. 48, No. 1 (2017)

• Uniqueness of Spacelike Hypersurfaces in a GRW Spacetime via Higher Order
Mean Curvatures
• Authors: Cícero P. Aquino; Jogli G. Araújo; Márcio Batista; Henrique F. de Lima
Pages: 45 - 61
Abstract: We study the problem of uniqueness concerning complete spacelike hypersurfaces immersed in a generalized Robertson–Walker (GRW) spacetime, whose fiber obeys suitable curvature constraints. In this setting, we apply some maximum principles in order to guarantee that such a spacelike hypersurface must be a slice of the ambient space, provided that some of their higher order mean curvatures satisfies appropriated controls. Furthermore, we also establish nonparametric results concerning entire spacelike graphs in GRW spacetimes.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0004-x
Issue No: Vol. 48, No. 1 (2017)

• Bounded Limit Cycles of Polynomial Foliations of $$\mathbb {C}^{2}$$ C 2
• Authors: Nataliya Goncharuk; Yury Kudryashov
Pages: 63 - 83
Abstract: In this article we prove in a new way that a generic polynomial vector field in $$\mathbb {C}^{2}$$ possesses countably many homologically independent limit cycles. The new proof needs no estimates on integrals, provides thinner exceptional set for quadratic vector fields, and provides limit cycles that stay in a bounded domain.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0005-9
Issue No: Vol. 48, No. 1 (2017)

• Foliations on Modular Curves
• Authors: Igor V. Nikolaev
Pages: 85 - 92
Abstract: It is proved, that a foliation on a modular curve given by the vertical trajectories of holomorphic differential corresponding to the Hecke eigenform is either the Strebel foliation or the pseudo-Anosov foliation.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0006-8
Issue No: Vol. 48, No. 1 (2017)

• Points on singular Frobenius nonclassical curves
• Authors: Herivelto Borges; Masaaki Homma
Pages: 93 - 101
Abstract: In 1990, Hefez and Voloch proved that the number of $$\mathbb {F}_q$$ -rational points on a nonsingular plane q-Frobenius nonclassical curve of degree d is $$N=d(q-d+2)$$ . We address these curves in the singular setting. In particular, we prove that $$d(q-d+2)$$ is a lower bound on the number of $$\mathbb {F}_q$$ -rational points on such curves of degree d.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0008-6
Issue No: Vol. 48, No. 1 (2017)

• Positive Neighborhoods of Rational Curves
• Authors: M. Falla Luza; P. Sad
Pages: 103 - 110
Abstract: We study neighborhoods of rational curves in surfaces with self-intersection number 1 that can be linearised.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0009-5
Issue No: Vol. 48, No. 1 (2017)

• On Weakly Hyperbolic Iterated Function Systems
• Authors: Alexander Arbieto; André Junqueira; Bruno Santiago
Pages: 111 - 140
Abstract: We study weakly hyperbolic iterated function systems on compact metric spaces, as defined by Edalat (Inform Comput 124(2):182–197, 1996), but in the more general setting of compact parameter space. We prove the existence of attractors, both in the topological and measure theoretical viewpoint and the ergodicity of invariant measure. We also define weakly hyperbolic iterated function systems for complete metric spaces and compact parameter space, extending the above mentioned definition. Furthermore, we study the question of existence of attractors in this setting. Finally, we prove a version of the results by Barnsley and Vince (Ergodic Theory Dyn Syst 31(4):1073–1079, 2011), about drawing the attractor (the so-called the chaos game), for compact parameter space.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0018-4
Issue No: Vol. 48, No. 1 (2017)

• On the Constants of the Bohnenblust–Hille and Hardy–Littlewood
Inequalities
• Authors: Gustavo Araújo; Daniel Pellegrino
Pages: 141 - 169
Abstract: For $$\mathbb {K}=\mathbb {R}$$ or $$\mathbb {C}$$ , the Hardy–Littlewood inequality for m-linear forms asserts that for $$4\le 2m\le p\le \infty$$ there exists a constant $$C_{m,p}^{\mathbb {K}}\ge 1$$ such that, for all m-linear forms $$T:\ell _{p}^{n}\times \cdots \times \ell _{p}^{n}\rightarrow \mathbb {K}$$ , and all positive integers n, This result was proved by Hardy and Littlewood (QJ Math 5:241–254, 1934) for bilinear forms and extended to m-linear forms by Praciano-Pereira (J Math Anal Appl 81:561–568, 1981). The case $$p=\infty$$ recovers the Bohnenblust–Hille inequality (Ann Math 32:600–622, 1931). In this paper, among other results, we show that for $$p>2m(m-1)^2$$ the optimal constants satisfying the Hardy–Littlewood inequality for m-linear forms are dominated by the best known constants of the corresponding Bohnenblust–Hille inequality. For instance, we show that if $$p>2m(m-1)^2$$ , then \begin{aligned} \textstyle C_{m,p}^{\mathbb {C}}\le \prod \limits _{j=2}^{m}\Gamma \left( 2-\frac{1}{j}\right) ^{\frac{j}{2-2j}}<m^{\frac{1-\gamma }{2}}, \end{aligned} where $$\gamma$$ is the Euler–Mascheroni constant.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0016-6
Issue No: Vol. 48, No. 1 (2017)

• Sharp Constant of an Anisotropic Gagliardo–Nirenberg-Type Inequality
and Applications
• Authors: Amin Esfahani; Ademir Pastor
Pages: 171 - 185
Abstract: In this paper we establish the best constant of an anisotropic Gagliardo–Nirenberg-type inequality related to the Benjamin–Ono–Zakharov–Kuznetsov equation. As an application of our results, we prove the uniform bound of solutions for such a equation in the energy space.
PubDate: 2017-03-01
DOI: 10.1007/s00574-016-0017-5
Issue No: Vol. 48, No. 1 (2017)

• Properties of Shadowable Points: Chaos and Equicontinuity
• Authors: Noriaki Kawaguchi
Abstract: We extend the study on shadowable points recently introduced by Morales in relation to chaotic or non-chaotic properties. Firstly, some sufficient conditions for a quantitative shadowable point to be approximated by an entropy point are given. As a corollary, we get different three chaotic conditions from which a shadowable point becomes an entropy point. Secondly, we provide a dichotomy on the interior of the set of shadowable chain recurrent points by two canonical chaotic and non-chaotic dynamics, the full shift and odometers.
PubDate: 2017-03-24
DOI: 10.1007/s00574-017-0033-0

• Induced Hausdorff Metrics on Quotient Spaces
• Authors: Ryuichi Fukuoka; Djeison Benetti
Abstract: Let G be a group, (M, d) be a metric space, $$X\subset M$$ be a compact subset and $$\varphi :G\times M\rightarrow M$$ be a left action of G on M by homeomorphisms. Denote $$gp=\varphi (g,p)$$ . The isotropy subgroup of G with respect to X is defined by $$H_X=\{g\in G; gX=X\}$$ . In this work we define the induced Hausdorff metric on $$G/H_X$$ by $$d_X(g_1H_X,g_2H_X):=d_H(g_1X,g_2X)$$ , where $$d_H$$ is the Hausdorff distance on M. Let $$\hat{d}_X$$ be the intrinsic metric induced by $$d_X$$ . In this work, we study the geometry of $$(G/H_X,d_X)$$ and $$(G/H_X,\hat{d}_X)$$ and their relationship with (M, d). In particular, we prove that if G is a Lie group, M is a differentiable manifold endowed with a metric which is locally Lipschitz equivalent to a Finsler metric, $$X\subset M$$ is a compact subset and $$\varphi :G\times M\rightarrow M$$ is a smooth left action by isometries, then $$(G/H_X,\hat{d}_X)$$ is a $$C^0$$ -Finsler manifold. We also calculate the Finsler metric explicitly in some examples.
PubDate: 2017-03-22
DOI: 10.1007/s00574-017-0032-1

• Pontryagin’s Risk-Sensitive Stochastic Maximum Principle for Backward
Stochastic Differential Equations with Application
Abstract: This paper studies the risk-sensitive optimal control problem for a backward stochastic system. More precisely, we set up a necessary stochastic maximum principle for a risk-sensitive optimal control of this kind of equations. The control domain is assumed to be convex and the generator coefficient of such system is allowed to be depend on the control variable. As a preliminary step, we study the risk-neutral problem for which an optimal solution exists. This is an extension of initial control system to this type of problem, where the set of admissible controls is convex. An example to carried out to illustrate our main result of risk-sensitive control problem under linear stochastic dynamics with exponential quadratic cost function.
PubDate: 2017-02-23
DOI: 10.1007/s00574-017-0031-2

• Non-Homogeneous Thermoelastic Timoshenko Systems
• Authors: M. S. Alves; M. A. Jorge Silva; T. F. Ma; J. E. Muñoz Rivera
Abstract: The well-established Timoshenko system is characterized by a particular relation between shear stress and bending moment from its constitutive equations. Accordingly, a (thermal) dissipation added on the bending moment produces exponential stability if and only if the so called “equal wave speeds” condition is satisfied. This remarkable property extends to the case of non-homogeneous coefficients. In this paper, we consider a non-homogeneous thermoelastic system with dissipation restricted to the shear stress. To this new problem, by means of a delicate control observability analysis, we prove that a local version of the equal wave speeds condition is sufficient for the exponential stability of the system. Otherwise, we study the polynomial stability of the system with decay rate depending on the regularity of initial data.
PubDate: 2017-02-10
DOI: 10.1007/s00574-017-0030-3

• New Irreducible Components of the Space of Foliations Associated to the
Affine Lie Algebra
• Authors: Ruben Lizarbe
Abstract: We construct a family of irreducible components of space of holomorphic foliations of codimension one on $$\mathbb {P}^3$$ associated to some affine Lie algebra.
PubDate: 2017-01-31
DOI: 10.1007/s00574-017-0029-9

• Burnside Problem for Groups of Homeomorphisms of Compact Surfaces
• Authors: Nancy Guelman; Isabelle Liousse
Abstract: A group $$\Gamma$$ is said to be periodic if for any g in $$\Gamma$$ there is a positive integer n with $$g^n=id$$ . We first prove that a finitely generated periodic group acting on the 2-sphere $${\mathbb S}^2$$ by $$C^1$$ -diffeomorphisms with a finite orbit, is finite and $$C^1$$ -conjugate to a subgroup of $$\mathrm {O}(3,{\mathbb R})$$ . This result is obtained by proving the more general statement: a finitely generated periodic group acting on any compact manifold by $$C^1$$ -diffeomorphisms with a finite orbit, is finite. We use it for proving that a countable 2-group of spherical diffeomorphisms with bounded orders is finite. This gives a negative partial answer to a question posed by D. Fisher. Finally, we show that a finitely generated periodic group of homeomorphisms of any orientable compact surface other than the 2-sphere or the 2-torus is finite.
PubDate: 2017-01-26
DOI: 10.1007/s00574-017-0028-x

• On Equilibrium States for Partially Hyperbolic Horseshoes: Uniqueness and
Statistical Properties
• Authors: V. Ramos; J. Siqueira
Abstract: We prove uniqueness of equilibrium states for a family of partially hyperbolic horseshoes associated to a class of Hölder continuous potentials with small variation and derive statistical properties for this unique equilibrium. We define a projection map associated to the horseshoe and prove a spectral gap for its transfer operator acting on some space of Hölder continuous observables. From this we deduce an exponential decay of correlations and a central limit theorem. We finally extend these results to the horseshoe via Rohlin’s disintegration of the equilibrium along the stable fibers.
PubDate: 2017-01-19
DOI: 10.1007/s00574-017-0027-y

• On the Structure of the Equivalent Differential Systems and their
Reflecting Integrals
• Authors: Zhengxin Zhou
Abstract: In this article, I have completely solved this problem: when one differential system is equivalent to a given differential system, what structure does this system and its reflecting integral have? At the same time, I have established the relationship between the reflecting integrals and the first integrals and integrating factors of the differential equations.
PubDate: 2016-12-26
DOI: 10.1007/s00574-016-0026-4

• On the Solvability of Third-Order Three Point Systems of Differential
Equations with Dependence on the First Derivative
• Authors: Feliz Minhós; Robert de Sousa
Abstract: This paper presents sufficient conditions for the solvability of the third order three point boundary value problem \begin{aligned} \left\{ \begin{array}{c} -u^{\prime \prime \prime }(t)=f(t,\,v(t),\,v^{\prime }(t)) \\ -v^{\prime \prime \prime }(t)=h(t,\,u(t),\,u^{\prime }(t)) \\ u(0)=u^{\prime }(0)=0,u^{\prime }(1)=\alpha u^{\prime }(\eta ) \\ v(0)=v^{\prime }(0)=0,v^{\prime }(1)=\alpha v^{\prime }(\eta ). \end{array} \right. \end{aligned} The arguments apply Green’s function associated to the linear problem and the Guo–Krasnosel’skiĭ theorem of compression-expansion cones. The dependence on the first derivatives is overcome by the construction of an adequate cone and suitable conditions of superlinearity/sublinearity near 0 and $$+\infty$$ . Last section contains an example to illustrate the applicability of the theorem.
PubDate: 2016-12-22
DOI: 10.1007/s00574-016-0025-5

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327

Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs