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We discuss criteria for the nonexistence, existence and computation of invariant algebraic surfaces for three-dimensional complex polynomial vector fields, thus transferring a classical problem of Poincar\'e from dimension two to dimension…

Dynamical Systems · Mathematics 2019-07-30 Niclas Kruff , Jaume Llibre , Chara Pantazi , Sebastian Walcher

This paper deals with an improvement of the "a-priori stability bounds" on the variation of the action variables and on the stability time obtained from a given Birkhoff normal form around the elliptic equilibrium point of an Hamiltonian…

Dynamical Systems · Mathematics 2026-01-27 Massimiliano Guzzo , Chiara Caracciolo , Gabriella Pinzari

Summary: A system of autonomous ordinary differential equations depending on a small parameter is considered such that the unperturbed system has an invariant manifold of periodic solutions that is not normally hyperbolic but is normally…

chao-dyn · Physics 2008-02-03 Carmen Chicone

For the space of single-variable monic and centered complex polynomial vector fields of arbitrary degree d, it is proved that any bifurcation which preserves the multiplicity of equilibrium points can be realized as a composition of a…

Dynamical Systems · Mathematics 2020-09-14 Kealey Dias

Consider in R^2 the semi-planes N={y>0} and S={y<0}$ having as common boundary the straight line D={y=0}$. In N and S are defined polynomial vector fields X and Y, respectively, leading to a discontinuous piecewise polynomial vector field…

Dynamical Systems · Mathematics 2012-09-20 Claudio Pessoa , Jorge Sotomayor

We study the effect of external forcing on the saddle-node bifurcation pattern of interval maps. By replacing fixed points of unperturbed maps by invariant graphs, we obtain direct analogues to the classical result both for random forcing…

Dynamical Systems · Mathematics 2011-05-26 Vasso Anagnostopoulou , Tobias Jäger

We give conditions under which nonuniformly expanding maps exhibit lower bounds of polynomial type for the decay of correlations and for a large class of observables. We show that if the Lasota-Yorke type inequality for the transfer…

Dynamical Systems · Mathematics 2017-09-28 Huyi Hu , Sandro Vaienti

For a faithful linear representation $V$ of a finite group $G$ in coprime characteristic, we show that if the field Noether number $\beta_{\mathrm{field}}$ is the minimum $d$ such that the invariant polynomials of degree $\leq d$ generate…

Commutative Algebra · Mathematics 2026-05-18 Ben Blum-Smith , Harm Derksen

The periodic table is a fundamental representation of chemical elements that plays essential theoretical and practical roles. The research article discusses the experiences of unsupervised training of neural networks to represent elements…

Machine Learning · Computer Science 2025-01-24 Alex Glushkovsky

Near full-null degenerate singular points of analytic vector fields, asymptotic behaviors of orbits are not given by eigenvectors but totally decided by nonlinearities. Especially, in the case of high full-null degeneracy, i.e., the lowest…

Dynamical Systems · Mathematics 2023-09-19 Jun Zhang , Xingwu Chen , Weinian Zhang

Let $\varphi: \mathbb{P}^{n}_{F} \to \mathbb{P}^{n}_{F}$ where $F$ is a complete valued field. If $x$ is a fixed point, such that the action of $\varphi$ on $T_{x}$ has eigenvalues $\lambda_{1}, \ldots, \lambda_{n}$, with $\lambda_{1},…

Number Theory · Mathematics 2015-11-04 Alon Levy

This paper develops a new method for identifying econometric models with partially latent covariates. Such data structures arise in industrial organization and labor economics settings where data are collected using an input-based sampling…

Econometrics · Economics 2022-06-29 Minji Bang , Wayne Yuan Gao , Andrew Postlewaite , Holger Sieg

Associated to analytic Hamiltonian vector fields in $\mathbb{C}^4$ having an equilibrium point satisfying a non semisimple $1:-1$ resonance, we construct two universal constants that are invariant with respect to local analytic symplectic…

Dynamical Systems · Mathematics 2013-04-30 Jose Pedro Gaivao

Let $G$ be a bounded open subset of Euclidean space with real algebraic boundary $\Gamma$. Under the assumption that the degree $d$ of $\Gamma$ is given, and the power moments of the Lebesgue measure on $G$ are known up to order $3d$, we…

Optimization and Control · Mathematics 2014-02-07 Jean-Bernard Lasserre , Mihai Putinar

In this paper we give a smooth linearization theorem for nonautonomous differential equations with a nonuniform strong exponential dichotomy. In terms of discretized evolution operator with hyperbolic fixed point 0, we formulate its…

Dynamical Systems · Mathematics 2019-12-11 Davor Dragicevic , Weinian Zhang , Wenmeng Zhang

We show that certain linear elliptic equations (and systems) in divergence form with almost periodic coefficients have bounded, almost periodic correctors. This is proved under a new condition we introduce which quantifies the almost…

Analysis of PDEs · Mathematics 2016-05-25 Scott Armstrong , Antoine Gloria , Tuomo Kuusi

Recently it has been advocated [1] that for describing nature within the minimal symmetry requirement, certain subgroups of Lorentz group may play a fundamental role. One such group is E(2) which induces a Lie algebraic Non-Commutative…

High Energy Physics - Theory · Physics 2009-12-31 Subir Ghosh , And Probir Pal

The $P_1$--nonconforming quadrilateral finite element space with periodic boundary condition is investigated. The dimension and basis for the space are characterized with the concept of minimally essential discrete boundary conditions. We…

Numerical Analysis · Mathematics 2022-01-27 Jaeryun Yim , Dongwoo Sheen

Decoupling inequalities disentangle complex dependence structures of random objects so that they can be analyzed by means of standard tools from the theory of independent random variables. We study decoupling inequalities for vector-valued…

Functional Analysis · Mathematics 2021-01-01 Daniel Carando , Felipe Marceca , Pablo Sevilla-Peris

Many time-dependent linear partial differential equations of mathematical physics and continuum mechanics can be phrased in the form of an abstract evolutionary system defined on a Hilbert space. In this paper we discuss a general framework…

Analysis of PDEs · Mathematics 2019-05-09 Stefan Neukamm , Mario Varga , Marcus Waurick