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Browsing DMAT - Artículos by Title
Now showing items 1-20 of 26
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A New Normal Form for Monodromic Nilpotent Singularities of Planar Vector Fields
Algaba Durán, Antonio
; García García, Cristóbal; Giné, Jaume (Springer, 2021)
In this work, we present a new technique for solving the center problem for nilpotent singularities which consists of determining a new normal form conveniently adapted to study the center problem for this singularity. In ... -
A Value for Graph-Restricted Games with Middlemen on Edges
(MDPI, 2022)In a cooperative game with a communication structure, a graph describes the communication possibilities of the players, which are represented by the nodes. We introduce a variation of this model by assuming that each ... -
Algebraic integrability of nilpotent planar vector fields
Algaba Durán, Antonio; García García, Cristóbal, Matemático; Reyes Columé, Manuel (Elsevier, 2021)
We characterize, using normal forms of quasi-homogeneous expansions, the analytic vector fields at nilpotent singular point having an algebraic first integral over the ring C [[ x, y ]] . As a consequence, we provide a ... -
Analysis of the T-point-Hopf bifurcation with Z2-symmetry : application to chua's equation
Algaba Durán, Antonio; Fernández Sánchez, Fernando; Merino Morlesín, Manuel; Rodríguez Luis, Alejandro José (World Scientific, 2010)
The aim of this work is twofold - on the one hand, to perform a theoretical analysis of the global behavior organized by a T-point-Hopf in Z(2)-symmetric systems; on the other hand, to apply the obtained results for a ... -
Analytic integrability inside a family of degenerate centers
Algaba Durán, Antonio; Checa Camacho, Isabel; García García, Cristóbal; Giné, Jaume (Elsevier, 2016)
In this paper we study the analytic integrability around the origin inside a family of degenerate centers or perturbations of them. For this family analytic integrability does not imply formal orbital equivalence to a ... -
Analytic Integrability of Some Examples of Degenerate Planar Vector Fields
Algaba Durán, Antonio; García García, Cristóbal; Giné, Jaume (Springer, 2016)
This paper is devoted to the classification of analytic integrable cases of two families of degenerate planar vector fields with a monodromic singular point at the origin. This study falls in the still open degenerate ... -
Analytic partial-integrability of a symmetric Hopf-zero degeneracy
Algaba Durán, Antonio; García García, Cristóbal; Reyes Columé, Manuel (Cambridge University Press, 2022)
We deal with analytic three-dimensional symmetric systems whose origin is a Hopf-zero singularity. Once it is not completely analytically integrable, we provide criteria on the existence of at least one functionally ... -
Center problem for generic degenerate vector fields
Algaba Durán, Antonio; Díaz García, María; García García, Cristóbal; Giné, Jaume (Elsevier, 2022)
We generalize the method of construction of an integrating factor for Abel differential equations, developed in Briskin et al. (1998), for any generic monodromic singularity. Here generic means that the vector field has ... -
Detecting the optic disc boundary in digital fundus images using morphological, edge detection, and feature extraction techniques
Gegúndez Arias, Manuel Emilio; Marín Santos, Diego; Aquino Martín, Arturo (IEEE, 2010-11)
Optic disc (OD) detection is an important step in developing systems for automated diagnosis of various serious ophthalmic pathologies. This paper presents a new template-based methodology for segmenting the OD from digital ... -
Double-zero degeneracy and heteroclinic cycles in a perturbation of the Lorenz system
Algaba Durán, Antonio; Domínguez Moreno, María Cinta; Merino Morlesín, Manuel; Rodríguez Luis, Alejandro José (Elsevier, 2022)
In this paper we consider a 3D three-parameter unfolding close to the normal form of the triple-zero bifurcation exhibited by the Lorenz system. First we study analytically the double-zero degeneracy (a double-zero ... -
Integrability of planar nilpotent differential systems through the existence of an inverse integrating factor
Algaba Durán, Antonio; García García, Cristóbal; Giné, Jaume (Elsevier, 2019)
In this work is characterized the analytic integrability problem around a nilpotent singularity for differential systems in the plane under generic conditions. The analytic integrability problem is characterized via the ... -
Integrability of two dimensional quasi-homogeneous polynomial differential systems
Algaba Durán, Antonio; García García, Cristóbal, Matemático; Reyes Columé, Manuel (Rocky Mountain Mathematics Consortium, 2011)
In terms of the conservative-dissipative de composition of a vector field, we characterize the two dimensional quasi-homogeneous polynomial differential systems with a polynomial first integral (in these systems, polynomial ... -
Matemáticas en contexto en Educación Primaria: conexiones con el entorno y la música
Alsina, Ángel; Contreras, Manuela; Reyes Columé, Joaquín (Federación Iberoamericana de Sociedades de Educación Matemática (FISEM), 2022-04)
Se describe un enfoque competencial de la enseñanza de las matemáticas en Educación Primaria a partir de actividades contextualizadas. Para ello, en la primera parte se fundamenta teóricamente el conocimiento pedagógico ... -
Modelización matemática en secundaria desde un punto de vista superior: EL PROBLEMA DE DOBOGÓKÓ
Romero Sánchez, Sixto; Castro Gutiérrez, Fernando (Universitat Politècnica de València, 2008-12)
El presente trabajo describe y analiza una experiencia de modelización matemática que bien podría desarrollarse en el aula con alumnos de secundaria. Las distintas etapas del proceso de modelización seguido se describen ... -
A new supervised method for blood vessel segmentation in retinal images by using gray-level and moment invariants-based features
Marín Santos, Diego; Gegúndez Arias, Manuel Emilio; Bravo Caro, José Manuel; Aquino Martín, Arturo (IEEE, 2011-01)
This paper presents a new supervised method for blood vessel detection in digital retinal images. This method uses a neural network (NN) scheme for pixel classification and computes a 7-D vector composed of gray-level and ... -
Nilpotent Systems Admitting an Algebraic Inverse Integrating Factor over C((x,y))
Algaba Durán, Antonio; García García, Cristóbal, Matemático; Reyes Columé, Manuel (Springer Verlag, 2011)
We characterize the nilpotent systems whose lowest degree quasihomogeneous term is (y, σ xn)T, σ = ±1, which have an algebraic inverse integrating factor over C((x,y)) . In such cases, we show that the systems admit an ... -
On multiplying curves in the Kauffman bracket skein algebra of the thickened four-holed sphere
(World Scientific Publishing, 2022)Based on the presentation of the Kauffman bracket skein algebra of the thickened torus given by the third author in previous work [4], Frohman and Gelca established a complete description of the multiplicative operation ... -
On the Formal Integrability Problem for Planar Differential Systems
Algaba Durán, Antonio; García García, Cristóbal; Giné, Jaume (Hindawi Publishing Corporation, 2013)
We study the analytic integrability problem through the formal integrability problem and we show its connection, in some cases, with the existence of invariant analytic (sometimes algebraic) curves. From the results obtained, ... -
On the Integrability Problem for the Hopf-Zero singularity and its relation with the inverse Jacobi multiplier
Algaba Durán, Antonio; Fuentes Díaz, Natalia; Gamero, Estanislao; García García, Cristóbal (Elsevier, 2021)
In this paper we use the orbital normal form of the nondegenerate Hopf-zero singularity to obtain necessary conditions for the existence of first integrals for such singularity. Also, we analyze the relation between the ... -
Orbital Hypernormal Forms
Algaba Durán, Antonio; Gamero, Estanislao; García García, Cristóbal (MDPI, 2021)
In this paper, we analyze the problem of determining orbital hypernormal forms—that is, the simplest analytical expression that can be obtained for a given autonomous system around an isolated equilibrium point through ...
