Exploració per autor "Pantazi, Chara"
Ara es mostren els items 5-24 de 32
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Darboux integrability and dynamics of the Basener–Ross population model
Güngör, Faruk; Llibre Saló, Jaume; Pantazi, Chara (Circolo Matematico di Palermo, 2021)
Article
Accés obertWe deal with the Basener and Ross model for the evolution of human population in Easter island. We study the Darboux integrability of this model and characterize all its global dynamics in the Poincaré disc, obtaining 15 ... -
Darboux integrability and invariant algebraic curves for planar polynomial systems
Christopher, C.; Llibre Saló, Jaume; Pantazi, Chara; Zhang, Xiang (2004)
Article
Accés obertIn this paper we study the normal forms of polynomial systems having a set of given generic invariant algebraic curves. -
Darboux integrals for Schrödinger planar vector fields via Darboux transformations
Acosta Humánez, Primitivo Belén; Pantazi, Chara (2011-11-01)
Report de recerca
Accés obertIn this paper we study the Darboux transformations of planar vector fields of Schrödinger type. Using the isogaloisian property of Darboux transformation we prove the “invariance” of the elements of the “Darboux Theory of ... -
Darboux integrals for Schrödinger planar vector fields via Darboux transformations
Acosta Humánez, Primitivo Belén; Pantazi, Chara (2012-07-14)
Article
Accés obertIn this paper we study the Darboux transformations of planar vector fields of Schr odinger type. Using the isogaloisian property of Darboux transformation we prove the \invariance" of the objects of the \Darboux theory ... -
Darboux theory of integrability for a class of nonautonomous vector fields
Llibre Saló, Jaume; Pantazi, Chara (2009-10)
Article
Accés obertThe goal of this paper is to extend the classical Darboux theory of integrability from autonomous polynomial vector fields to a class of nonautonomous vector fields. We also provide sufficient conditions for applying ... -
Differential galois theory and non-integrability of planar polynomial vector fields
Lázaro Ochoa, José Tomás; Pantazi, Chara; Acosta Humanez, Primitivo; Morales Ruiz, Juan José (2018-02-26)
Article
Accés restringit per política de l'editorialWe study a necessary condition for the integrability of the polynomials vector fields in the plane by means of the differential Galois Theory. More concretely, by means of the variational equations around a particular ... -
EngiMath online course. Effective feedback from UPC mathematics teachers
Serrat Piè, Carles; Estela Carbonell, M. Rosa; Bruguera Padró, Maria Montserrat; Pantazi, Chara (Universitat Politècnica de Catalunya, 2022-09)
Text en actes de congrés
Accés obertEngiMath is a 3 ECTS online course in engineering mathematics, in seven different languages, and it is the main and practical output of the ERASMUS+ project entitled “Mathematics online learning model in engineering ... -
EngiMath online course. Effective feedback from upc mathematics teachers (concept)
Serrat Piè, Carles; Estela Carbonell, M. Rosa; Bruguera Padró, Maria Montserrat; Pantazi, Chara (Universitat Politècnica de Catalunya, 2022-09)
Text en actes de congrés
Accés obertEngiMath is a 3 ECTS online course in engineering mathematics, in seven different languages, and it is the main and practical output of the ERASMUS+ project entitled “Mathematics online learning model in engineering ... -
Global phase portraits of the quadratic systems having a singular and irreducible invariant curve of degree 3
Pantazi, Chara; Llibre Saló, Jaume (2023-01)
Article
Accés obertAny singular irreducible cubic curve (or simply, cubic) after an affine transformation can be written as either y2=x3 , or y2=x2(x+1) , or y2=x2(x-1) . We classify the phase portraits of all quadratic polynomial differential ... -
Integrability and dynamics of a simplified class B laser system
Llibre Saló, Jaume; Pantazi, Chara (American Institute of Physics (AIP), 2023-10-12)
Article
Accés obertA simplified class B laser system is a family of differential polynomial systems of degree two depending on the parameters a and b. Its rich dynamics has already been observed in 1980s, see Arecchi et al. [Opt. Commun. 51, ... -
Integrability and linearizability of a family of three-dimensional quadratic systems
Pantazi, Chara; Amen, Azad; Aziz, Waleed (2021-01-01)
Article
Accés obertWe consider a three-dimensional vector field with quadratic nonlinearities and in general none of the axis plane is invariant. For our investigation, we are interesting in the case of (1:-2:1) – resonance at the origin. ... -
Invariant algebraic surfaces of polynomial vector fields in dimension three
Kruff, Niclas; Llibre Saló, Jaume; Pantazi, Chara; Walcher, Sebastian (Springer, 2021-01-01)
Article
Accés obertWe 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 Poincaré from dimension ... -
Limit cycles bifurcating from a degenerate center
Llibre Saló, Jaume; Pantazi, Chara (2016-02-01)
Article
Accés obertWe study the maximum number of limit cycles that can bifurcate from a degenerate center of a cubic homogeneous polynomial differential system. Using the averaging method of second order and perturbing inside the class of ... -
Morphisms and inverse problems
Christopher, Colin; Llibre Saló, Jaume; Pantazi, Chara; Walcher, Sebastian (2011-11-03)
Report de recerca
Accés obertIn order to investigate polynomial vector ¯elds admitting a prescribed Darboux integrating factor, we show that it is helpful to employ morphisms of the a±ne plane. In particular, such morphisms may be used to remove ... -
Morphisms and inverse problems for Darboux integrating factors
Llibre Saló, Jaume; Pantazi, Chara; Walcher, Sebastian (2013-12)
Article
Accés obertPolynomial vector fields which admit a prescribed Darboux integrat- ing factor are quite well-understood when the geometry of the underlying curve is nondegenerate. In the general setting morphisms of the affine plane ... -
On planar polynomial vector fields with elementary first integrals
Christopher, Colin; Pantazi, Chara; Llibre Saló, Jaume; Walcher, Sebastian (2019-10-05)
Article
Accés obertWe show that under rather general conditions a polynomial differential system having an elementary first integral already must admit a Darboux first integral, and we explicitly characterize the vector fields in this class. ... -
On the integrability of polynomial fields in the plane by means of Picard-Vessiot theory
Lázaro Ochoa, José Tomás; Morales Ruíz, Juan José; Acosta Humánez, Primitivo Belén; Pantazi, Chara (2012-01-12)
Report de recerca
Accés obertWe study the integrability of polynomial vector fields using Galois theory of linear differential equations when the associated foliations is reduced to a Riccati type foliation. In particular we obtain integrability results ... -
On the integrability of polynomial vector fields in the plane by means of Picard-Vessiot theory
Acosta-Humànez, Primitivo; Lázaro Ochoa, José Tomás; Morales Ruiz, Juan José; Pantazi, Chara (American Institute of Mathematical Sciences, 2015-05-01)
Article
Accés obertWe study the integrability of polynomial vector fields using Galois theory of linear differential equations when the associated foliations is reduced to a Riccati type foliation. In particular we obtain integrability results ... -
Online engineering mathematics course : development and implementation of a successful project
Soares, Filomena; Lopes, Ana Paula; Cellmer, Anna; Uukkivi, Anne; Serrat Piè, Carles; Pantazi, Chara; Feniser, Cristina; Safiulina, Elena; Serdean, Florina M.; Kierkosz, Igor; Kelly, Gerald; Cymerman, Joanna; Brown, Ken; Alier Forment, Marc; Bruguera Padró, Maria Montserrat; Estela Carbonell, M. Rosa; Labanova, Oksana; Bocanet, Vlad I.; Volodymyr, Sushch; Martin, Errol (International Association of Technology, Education and Development (IATED), 2022)
Comunicació de congrés
Accés obertAccording to the New UNESCO global survey studying the effect of Covid-19 on higher education (2021) the pandemic has had an impact on higher education systems in terms of access and quality of teaching and learning. ... -
Phase portraits of separable Hamiltonian systems
Guillamon Grabolosa, Antoni; Pantazi, Chara (Universidad de Sevilla, 2007-09)
Text en actes de congrés
Accés obertWe study some generalizations of potential Hamiltonian systems $(H(x, y) = y^2 + F(x))$ with one degree of freedom. In particular, we are interested in Hamiltonian systems with Hamiltonian functions of type $H(x, y) = ...