Edit Profile Ortega, Rafael Compute Distance To: Compute Author ID: ortega.rafael Published as: Ortega, R.; Ortega, Rafael External Links: MGP · ResearchGate · dblp Documents Indexed: 139 Publications since 1984, including 2 Books Reviewing Activity: 47 Reviews all top 5 Co-Authors 48 single-authored 8 Kannan, Rangachary 8 Kunze, Markus 7 Mawhin, Jean L. 6 Robles-Pérez, Aureliano M. 6 Tarallo, Massimo 6 Tineo, Antonio R. 5 Campos, Juan 5 Miguel-Alonso, Jose 4 Boscaggin, Alberto 4 Margheri, Alessandro 4 Rebelo, Carlota 3 Arias, Margarita 3 Dancer, Edward Norman 3 López-Gómez, Julián 3 Martinez-Amores, Pedro 2 Cañada Villar, Antonio 2 Cima, Anna 2 Fonda, Alessandro 2 Gasull, Armengol 2 Mañosas, Francesc 2 Rojas, David 2 Ruiz del Portal, Francisco Romero 2 Sanchez, Luis Angel 2 Verzini, Gianmaria 2 Zhao, Lei 1 Alonso, Ana Isabel 1 Amine, Zitan 1 Amster, Pablo 1 Barutello, Vivina L. 1 Buică, Adriana 1 Dambrosio, Walter 1 Delgado, Manuel 1 Enguiça, Ricardo Roque 1 Gebhard, Björn 1 Haddad, Julián 1 Hernández-Corbato, Luis 1 Llibre, Jaume 1 Makarenkov, Oleg Yuryĭovych 1 Misquero, Mauricio 1 Nuñez, Daniel E. 1 Obaya, Rafael 1 Ortega, Víctor 1 Rivera, Andrés M. 1 Ruiz-Herrera, Alfonso 1 Sánchez-Gabites, Jaime J. 1 Schmitt, Klaus 1 Serra, Enrico 1 Suárez, Antonio 1 Torres, Pedro José 1 Ureña, Antonio J. 1 Ward, James Robert jun. 1 Willem, Michel 1 Zanolin, Fabio 1 Zhang, Meirong 1 Zitan, Amine all top 5 Serials 11 Journal of Differential Equations 8 Proceedings of the American Mathematical Society 5 Journal of Mathematical Analysis and Applications 5 Differential and Integral Equations 5 Journal of Dynamics and Differential Equations 5 Nonlinear Analysis. Theory, Methods & Applications 4 Mathematical Proceedings of the Cambridge Philosophical Society 4 Nonlinearity 4 Annali di Matematica Pura ed Applicata. Serie Quarta 4 Ergodic Theory and Dynamical Systems 4 Advanced Nonlinear Studies 3 Proceedings of the London Mathematical Society. Third Series 3 Proceedings of the Royal Society of Edinburgh. Section A. Mathematics 3 Celestial Mechanics and Dynamical Astronomy 3 Discrete and Continuous Dynamical Systems 3 Discrete and Continuous Dynamical Systems. Series B 2 ZAMP. Zeitschrift für angewandte Mathematik und Physik 2 Archiv der Mathematik 2 Journal of the London Mathematical Society. Second Series 2 Rendiconti dell’Istituto di Matematica dell’Università di Trieste 2 Numerical Methods for Partial Differential Equations 2 Topological Methods in Nonlinear Analysis 2 Regular and Chaotic Dynamics 2 Communications in Contemporary Mathematics 2 Qualitative Theory of Dynamical Systems 2 Portugaliae Mathematica. Nova Série 2 SIAM Journal on Applied Dynamical Systems 1 Applicable Analysis 1 Rocky Mountain Journal of Mathematics 1 Advances in Mathematics 1 Bulletin of the London Mathematical Society 1 Czechoslovak Mathematical Journal 1 Journal of Functional Analysis 1 Journal of Mathematics of Kyoto University 1 Nonlinear Analysis. Theory, Methods & Applications. Series A: Theory and Methods 1 Rendiconti del Seminario Matemàtico e Fisico di Milano 1 Transactions of the American Mathematical Society 1 Bulletin de la Classe des Sciences. 5e Série 1 Journal de Mathématiques Pures et Appliquées. Neuvième Série 1 Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales de Madrid 1 SIAM Journal on Mathematical Analysis 1 Bollettino della Unione Matemàtica Italiana. Serie VII. B 1 Nonlinear World 1 NoDEA. Nonlinear Differential Equations and Applications 1 Advances in Differential Equations 1 Journal of the European Mathematical Society (JEMS) 1 Comptes Rendus. Mathématique. Académie des Sciences, Paris 1 RACSAM. Revista de la Real Academia de Ciencias Exactas, Físicas y Naturales. Serie A: Matemáticas 1 Communications on Pure and Applied Analysis 1 Rendiconti del Seminario Matematico. Universitá e Politecnico di Torino 1 De Gruyter Series in Nonlinear Analysis and Applications 1 Annals of the University of Bucharest. Mathematical Series all top 5 Fields 91 Ordinary differential equations (34-XX) 45 Dynamical systems and ergodic theory (37-XX) 25 Mechanics of particles and systems (70-XX) 22 Partial differential equations (35-XX) 9 Operator theory (47-XX) 7 Biology and other natural sciences (92-XX) 4 Difference and functional equations (39-XX) 3 Functions of a complex variable (30-XX) 3 Calculus of variations and optimal control; optimization (49-XX) 3 Global analysis, analysis on manifolds (58-XX) 2 Measure and integration (28-XX) 2 Algebraic topology (55-XX) 2 Numerical analysis (65-XX) 1 General and overarching topics; collections (00-XX) 1 History and biography (01-XX) 1 Integral equations (45-XX) 1 General topology (54-XX) 1 Manifolds and cell complexes (57-XX) 1 Probability theory and stochastic processes (60-XX) 1 Mechanics of deformable solids (74-XX) 1 Fluid mechanics (76-XX) 1 Statistical mechanics, structure of matter (82-XX) Publications by Year all cited Publications top 5 cited Publications Citations contained in zbMATH Open 111 Publications have been cited 1,084 times in 624 Documents Cited by ▼ Year ▼ Asymmetric oscillators and twist mappings. Zbl 0860.34017Ortega, Rafael 61 1996 Boundedness in a piecewise linear oscillator and a variant of the small twist theorem. Zbl 1030.34035Ortega, Rafael 55 1999 Roots of unity and unbounded motions of an asymmetric oscillator. Zbl 0899.34023Alonso, José Miguel; Ortega, Rafael 46 1998 The stability of the equilibrium of a nonlinear Hill’s equation. Zbl 0807.34065Ortega, Rafael 34 1994 The periodic predator-prey Lotka-Volterra model. Zbl 0849.34026López-Gómez, Julián; Ortega, Rafael; Tineo, Antonio 33 1996 Unbounded solutions of semilinear equations at resonance. Zbl 0896.34026Alonso, José Miguel; Ortega, Rafael 32 1996 Periodic solutions of a Newtonian equation: Stability by the third approximation. Zbl 0855.34058Ortega, Rafael 30 1996 Almost periodic linear differential equations with non-separated solutions. Zbl 1108.34008Ortega, Rafael; Tarallo, Massimo 29 2006 A maximum principle for periodic solutions of the telegraph equation. Zbl 0932.35016Ortega, Rafael; Robles-Pérez, Aureliano M. 27 1998 The index of Lyapunov stable fixed points in two dimensions. Zbl 0811.34018Dancer, E. N.; Ortega, R. 24 1994 Stability and index of periodic solutions of an equation of Duffing type. Zbl 0686.34052Ortega, Rafael 24 1989 A periodic prey-predator system. Zbl 0808.34043Amine, Zitan; Ortega, Rafael 21 1994 Invariant curves of mappings with averaged small twist. Zbl 1136.37336Ortega, Rafael 20 2001 Some applications of the topological degree to stability theory. Zbl 0834.34058Ortega, Rafael 19 1995 A maximum principle for bounded solutions of the telegraph equations and applications to nonlinear forcings. Zbl 0972.35016Mawhin, Jean; Ortega, Rafael; Robles-Pérez, Aureliano M. 18 2000 Parabolic fixed points and stability criteria for nonlinear Hill’s equation. Zbl 0973.34046Núñez, Daniel; Ortega, Rafael 17 2000 The twist coefficient of periodic solutions of a time-dependent Newton’s equation. Zbl 0761.34036Ortega, Rafael 17 1992 Topological degree and stability of periodic solutions for certain differential equations. Zbl 0677.34042Ortega, Rafael 16 1990 On the families of periodic orbits of the Sitnikov problem. Zbl 1159.70010Llibre, Jaume; Ortega, Rafael 14 2008 Maximum principles for bounded solutions of the telegraph equation in space dimensions two and three and applications. Zbl 1082.35040Mawhin, Jean; Ortega, Rafael; Robles-Pérez, Aureliano M. 14 2005 Almost periodic upper and lower solutions. Zbl 1043.34046Ortega, Rafael; Tarallo, Massimo 14 2003 Bounded solutions of second order semilinear evolution equations and applications to the telegraph equation. Zbl 0927.34048Alonso, Jose Miguel; Mawhin, Jean; Ortega, Rafael 14 1999 Optimal bounds for bifurcation values of a superlinear periodic problem. Zbl 1088.34036Ortega, Rafael; Zhang, Meirong 13 2005 Abstract competitive systems and orbital stability in \(\mathbb R^3\). Zbl 0951.34032Ortega, Rafael; Sánchez, Luis Ángel 13 2000 Boundedness and global asymptotic stability of a forced oscillator. Zbl 0826.34043Alonso, Jose Miguel; Ortega, Rafael 13 1995 The first interval of stability of a periodic equation of Duffing type. Zbl 0757.34035Ortega, Rafael 13 1992 Linear motions in a periodically forced Kepler problem. Zbl 1235.34136Ortega, Rafael 12 2011 A variational method for the existence of bounded solutions of a sublinear forced oscillator. Zbl 1072.34038Ortega, Rafael; Verzini, Gianmaria 12 2004 Existence of asymptotically stable periodic solutions of a forced equation of Liénard type. Zbl 0802.34050Zitan, Amine; Ortega, Rafael 12 1994 A counterexample for the damped pendulum equation. Zbl 0679.70022Ortega, R. 12 1987 Homeomorphisms of the disk with trivial dynamics and extinction of competitive systems. Zbl 0886.34025Campos, Juan; Ortega, Rafael; Tineo, Antonio 11 1997 Global asymptotic stability of a forced Newtonian system with dissipation. Zbl 0844.34047Alonso, José Miguel; Ortega, Rafael 11 1995 Degree theory and almost periodic problems. Zbl 1204.34054Ortega, Rafael 10 2008 Massera’s theorem for quasi-periodic differential equations. Zbl 1005.37021Ortega, Rafael; Tarallo, Massimo 10 2002 The number of stable periodic solutions of time-dependent Hamiltonian systems with one degree of freedom. Zbl 0946.34036Ortega, Rafael 10 1998 Stability of a periodic problem of Ambrosetti-Prodi type. Zbl 0724.34059Ortega, Rafael 10 1990 Differential equations with limit-periodic forcings. Zbl 1021.34015Alonso, Ana I.; Obaya, Rafael; Ortega, Rafael 9 2003 Periodic perturbations of an isochronous center. Zbl 1043.34049Ortega, Rafael 9 2002 Dynamics of a forced oscillator having an obstacle. Zbl 1054.34057Ortega, R. 9 2002 Non-continuation of the periodic oscillations of a forced pendulum in the presence of friction. Zbl 0970.34037Ortega, Rafael; Serra, Enrico; Tarallo, Massimo 9 2000 An exclusion principle for periodic competitive systems in three dimensions. Zbl 0901.34049Ortega, Rafael; Tineo, Antonio 9 1998 Resonance and non-resonance in a problem of boundedness. Zbl 0858.34018Ortega, Rafael; Tineo, Antonio 9 1996 A criterion for asymptotic stability based on topological degree. Zbl 0846.34056Ortega, Rafael 9 1996 Nonexistence of periodic solutions of a complex Riccati equation. Zbl 0842.34046Campos, Juan; Ortega, Rafael 9 1996 Existence of solutions of \(x''+x+g(x)=p(t)\), \(x(0)=0=x(\pi)\). Zbl 0585.34001Kannan, Rangachary; Ortega, Rafael 9 1986 Periodic solutions of pendulum-type equations. Zbl 0608.34047Kannan, Rangachary; Ortega, Rafael 9 1985 Global bifurcations from the center of mass in the Sitnikov problem. Zbl 1380.70028Ortega, Rafael; Rivera, Andrés 8 2010 Almost periodic equations and conditions of Ambrosetti-Prodi type. Zbl 1055.34085Ortega, Rafael; Tarallo, Massimo 8 2003 On the number of positive periodic solutions for planar competing Lotka-Volterra systems. Zbl 0903.34037Ortega, Rafael; Tineo, Antonio 8 1995 On the spectrum of some linear noncooperative elliptic systems with radial symmetry. Zbl 0841.35031Dancer, E. N.; López-Gómez, J.; Ortega, R. 8 1995 Generic results for the existence of nondegenerate periodic solutions of some differential systems with periodic nonlinearities. Zbl 0742.34043Martinez-Amores, P.; Mawhin, J.; Ortega, R.; Willem, M. 8 1991 Superlinear elliptic boundary value problems. Zbl 0668.35032Kannan, Rangachary; Ortega, Rafael 8 1987 Landesman-Lazer conditions for problems with “one-side unbounded” nonlinearities. Zbl 0624.35033Kannan, Rangachary; Ortega, Rafael 8 1985 Monotone twist maps and periodic solutions of systems of Duffing type. Zbl 1331.34070Boscaggin, Alberto; Ortega, Rafael 7 2014 A duality theorem for periodic solutions of a class of second order evolution equations. Zbl 1010.34054Ortega, Rafael; Robles-Pérez, Aureliano M. 7 2001 A forced pendulum equation with many periodic solutions. Zbl 0899.34031Ortega, Rafael 7 1997 Subharmonic solutions of the forced pendulum equation: a symplectic approach. Zbl 1303.34028Boscaggin, A.; Ortega, R.; Zanolin, F. 6 2014 Prevalence of non-degenerate periodic solutions in the forced pendulum equation. Zbl 1278.34042Ortega, Rafael 6 2013 Twist mappings with non-periodic angles. Zbl 1326.37032Kunze, Markus; Ortega, Rafael 6 2013 Attractors with vanishing rotation number. Zbl 1253.37048Ortega, Rafael; Ruiz del Portal, Francisco R. 6 2011 Asymptotic stability of forced oscillations emanating from a limit cycle. Zbl 1213.34060Makarenkov, Oleg; Ortega, Rafael 6 2011 Twist mappings, invariant curves and periodic differential equations. Zbl 1172.34326Ortega, Rafael 6 2001 A boundedness result of Landesman-Lazer type. Zbl 0817.34017Ortega, Rafael 6 1995 Existence theorems for equations in normed spaces and boundary value problems for nonlinear vector ordinary differential equations. Zbl 0558.47046Cañada, A.; Ortega, R. 6 1984 Persistence of equilibria as periodic solutions of forced systems. Zbl 1237.34077Buică, Adriana; Ortega, Rafael 5 2012 Periodic motions in forced problems of Kepler type. Zbl 1246.34035Amster, Pablo; Haddad, Julián; Ortega, Rafael; Ureña, Antonio J. 5 2011 Maximum principles around an eigenvalue with constant eigenfunctions. Zbl 1170.35029Campos, J.; Mawhin, J.; Ortega, R. 5 2008 Periodic solutions of a perturbed Kepler problem in the plane: from existence to stability. Zbl 1343.37045Boscaggin, Alberto; Ortega, Rafael 4 2016 Dynamics of Kepler problem with linear drag. Zbl 1298.70010Margheri, Alessandro; Ortega, Rafael; Rebelo, Carlota 4 2014 Stable periodic solutions in the forced pendulum equation. Zbl 1303.34031Ortega, Rafael 4 2013 Some analytical results about periodic orbits in the restricted three body problem with dissipation. Zbl 1266.70014Margheri, Alessandro; Ortega, Rafael; Rebelo, Carlota 4 2012 Complete orbits for twist maps on the plane: extensions and applications. Zbl 1228.37035Kunze, Markus; Ortega, Rafael 4 2011 Complete orbits for twist maps on the plane: the case of small twist. Zbl 1276.37035Kunze, Markus; Ortega, Rafael 4 2011 The pendulum equation: from periodic to almost periodic forcings. Zbl 1240.34222Ortega, Rafael 4 2009 Complete orbits for twist maps on the plane. Zbl 1149.37024Kunze, Markus; Ortega, Rafael 4 2008 On the number of solutions to semilinear boundary value problem. Zbl 1142.35425Kunze, Markus; Ortega, Rafael 4 2004 Nonexistence of radial solutions of two elliptic boundary value problems. Zbl 0721.35022Ortega, Rafael 4 1990 A finite difference approach to the equations of age-dependent population dynamics. Zbl 0677.65142Kannan, Rangachary; Ortega, Rafael 4 1989 Periodic solutions and regularization of a Kepler problem with time-dependent perturbation. Zbl 1422.37041Boscaggin, Alberto; Ortega, Rafael; Zhao, Lei 3 2019 Periodic differential equations in the plane. A topological perspective. Zbl 1427.34052Ortega, Rafael 3 2019 Periodic oscillators, isochronous centers and resonance. Zbl 1411.34051Ortega, Rafael; Rojas, David 3 2019 Point-vortex stability under the influence of an external periodic flow. Zbl 1393.37068Ortega, Rafael; Ortega, Víctor; Torres, Pedro J. 3 2018 Symmetric periodic solutions in the Sitnikov problem. Zbl 1354.34072Ortega, Rafael 3 2016 A forced pendulum equation without stable periodic solutions of a fixed period. Zbl 1323.34057Ortega, Rafael 3 2014 Long-time stability estimates for the non-periodic Littlewood boundedness problem. Zbl 1272.34043Kunze, Markus; Ortega, Rafael 3 2013 Stability and index of periodic solutions of a nonlinear telegraph equation. Zbl 1089.37046Ortega, Rafael 3 2005 Instability of periodic solutions obtained by minimization. Zbl 1210.37042Ortega, Rafael 3 2004 Periodic solutions of forced oscillators with several degrees of freedom. Zbl 1041.34003Ortega, Rafael; Sánchez, Luis A. 3 2002 Counting periodic solutions of the forced pendulum equation. Zbl 0967.34037Ortega, Rafael 3 2000 Positively homogeneous equations in the plane. Zbl 1079.34011Fonda, Alessandro; Ortega, Rafael 3 2000 On Littlewood’s problem for the asymmetric oscillator. Zbl 1020.34032Ortega, Rafael 3 1998 An asymptotic result in forced oscillations of pendulum-type equations. Zbl 0613.34028Kannan, Rangachary; Ortega, Rafael 3 1986 Linearization of planar involutions in \(\mathcal C^1\). Zbl 1352.37053Cima, A.; Gasull, A.; Mañosas, F.; Ortega, R. 2 2015 The complex periodic problem for a Riccati equation. Zbl 1274.34128Ortega, Rafael 2 2012 Index and persistence of stable Cantor sets. Zbl 1268.37069Ortega, Rafael; Ruiz-Herrera, Alfonso 2 2012 Retracts, fixed point index and differential equations. Zbl 1160.34049Ortega, Rafael 2 2008 A maximum principle for bounded solutions of the telegraph equation in space dimension three. Zbl 1002.35027Mawhin, Jean; Ortega, Rafael; Robles-Pérez, Aureliano M. 2 2002 Degenerate equations of pendulum-type. Zbl 0958.34033Ortega, Rafael; Tarallo, Massimo 2 2000 Nonexistence of invariant curves of mappings with small twist. Zbl 0907.58058Ortega, Rafael 2 1997 Doubly-periodic solutions of a forced semilinear wave equation. Zbl 0651.35057Arias, M.; Martínez-Amores, P.; Ortega, R. 2 1987 Periodic solutions and regularization of a Kepler problem with time-dependent perturbation. Zbl 1422.37041Boscaggin, Alberto; Ortega, Rafael; Zhao, Lei 3 2019 Periodic differential equations in the plane. A topological perspective. Zbl 1427.34052Ortega, Rafael 3 2019 Periodic oscillators, isochronous centers and resonance. Zbl 1411.34051Ortega, Rafael; Rojas, David 3 2019 Smooth linearisation of planar periodic maps. Zbl 1423.37027Cima, A.; Gasull, A.; Mañosas, F.; Ortega, R. 1 2019 Functions with average and bounded motions of a forced discontinuous oscillator. Zbl 1443.34020Enguiça, Ricardo; Ortega, Rafael 1 2019 Point-vortex stability under the influence of an external periodic flow. Zbl 1393.37068Ortega, Rafael; Ortega, Víctor; Torres, Pedro J. 3 2018 First integrals for the Kepler problem with linear drag. Zbl 1374.70025Margheri, Alessandro; Ortega, Rafael; Rebelo, Carlota 1 2017 Periodic solutions of a perturbed Kepler problem in the plane: from existence to stability. Zbl 1343.37045Boscaggin, Alberto; Ortega, Rafael 4 2016 Symmetric periodic solutions in the Sitnikov problem. Zbl 1354.34072Ortega, Rafael 3 2016 Linearization of planar involutions in \(\mathcal C^1\). Zbl 1352.37053Cima, A.; Gasull, A.; Mañosas, F.; Ortega, R. 2 2015 A homotopical property of attractors. Zbl 1362.37036Ortega, Rafael; Sánchez-Gabites, Jaime J. 1 2015 Monotone twist maps and periodic solutions of systems of Duffing type. Zbl 1331.34070Boscaggin, Alberto; Ortega, Rafael 7 2014 Subharmonic solutions of the forced pendulum equation: a symplectic approach. Zbl 1303.34028Boscaggin, A.; Ortega, R.; Zanolin, F. 6 2014 Dynamics of Kepler problem with linear drag. Zbl 1298.70010Margheri, Alessandro; Ortega, Rafael; Rebelo, Carlota 4 2014 A forced pendulum equation without stable periodic solutions of a fixed period. Zbl 1323.34057Ortega, Rafael 3 2014 Prevalence of non-degenerate periodic solutions in the forced pendulum equation. Zbl 1278.34042Ortega, Rafael 6 2013 Twist mappings with non-periodic angles. Zbl 1326.37032Kunze, Markus; Ortega, Rafael 6 2013 Stable periodic solutions in the forced pendulum equation. Zbl 1303.34031Ortega, Rafael 4 2013 Long-time stability estimates for the non-periodic Littlewood boundedness problem. Zbl 1272.34043Kunze, Markus; Ortega, Rafael 3 2013 Persistence of equilibria as periodic solutions of forced systems. Zbl 1237.34077Buică, Adriana; Ortega, Rafael 5 2012 Some analytical results about periodic orbits in the restricted three body problem with dissipation. Zbl 1266.70014Margheri, Alessandro; Ortega, Rafael; Rebelo, Carlota 4 2012 The complex periodic problem for a Riccati equation. Zbl 1274.34128Ortega, Rafael 2 2012 Index and persistence of stable Cantor sets. Zbl 1268.37069Ortega, Rafael; Ruiz-Herrera, Alfonso 2 2012 Attractors with irrational rotation number. Zbl 1267.37040Hernández-Corbato, Luis; Ortega, Rafael; Ruiz del Portal, Francisco R. 1 2012 Linear motions in a periodically forced Kepler problem. Zbl 1235.34136Ortega, Rafael 12 2011 Attractors with vanishing rotation number. Zbl 1253.37048Ortega, Rafael; Ruiz del Portal, Francisco R. 6 2011 Asymptotic stability of forced oscillations emanating from a limit cycle. Zbl 1213.34060Makarenkov, Oleg; Ortega, Rafael 6 2011 Periodic motions in forced problems of Kepler type. Zbl 1246.34035Amster, Pablo; Haddad, Julián; Ortega, Rafael; Ureña, Antonio J. 5 2011 Complete orbits for twist maps on the plane: extensions and applications. Zbl 1228.37035Kunze, Markus; Ortega, Rafael 4 2011 Complete orbits for twist maps on the plane: the case of small twist. Zbl 1276.37035Kunze, Markus; Ortega, Rafael 4 2011 A dynamical characterization of planar symmetries. Zbl 1273.37012Ortega, Rafael 1 2011 Global bifurcations from the center of mass in the Sitnikov problem. Zbl 1380.70028Ortega, Rafael; Rivera, Andrés 8 2010 The pendulum equation: from periodic to almost periodic forcings. Zbl 1240.34222Ortega, Rafael 4 2009 On the families of periodic orbits of the Sitnikov problem. Zbl 1159.70010Llibre, Jaume; Ortega, Rafael 14 2008 Degree theory and almost periodic problems. Zbl 1204.34054Ortega, Rafael 10 2008 Maximum principles around an eigenvalue with constant eigenfunctions. Zbl 1170.35029Campos, J.; Mawhin, J.; Ortega, R. 5 2008 Complete orbits for twist maps on the plane. Zbl 1149.37024Kunze, Markus; Ortega, Rafael 4 2008 Retracts, fixed point index and differential equations. Zbl 1160.34049Ortega, Rafael 2 2008 Location of fixed points and periodic solutions in the plane. Zbl 1360.34090Campos, Juan; Ortega, Rafael 1 2008 Almost periodic linear differential equations with non-separated solutions. Zbl 1108.34008Ortega, Rafael; Tarallo, Massimo 29 2006 Unbounded motions in forced Newtonian equations. Zbl 1103.34042Ortega, Rafael 1 2006 Maximum principles for bounded solutions of the telegraph equation in space dimensions two and three and applications. Zbl 1082.35040Mawhin, Jean; Ortega, Rafael; Robles-Pérez, Aureliano M. 14 2005 Optimal bounds for bifurcation values of a superlinear periodic problem. Zbl 1088.34036Ortega, Rafael; Zhang, Meirong 13 2005 Stability and index of periodic solutions of a nonlinear telegraph equation. Zbl 1089.37046Ortega, Rafael 3 2005 A variational method for the existence of bounded solutions of a sublinear forced oscillator. Zbl 1072.34038Ortega, Rafael; Verzini, Gianmaria 12 2004 On the number of solutions to semilinear boundary value problem. Zbl 1142.35425Kunze, Markus; Ortega, Rafael 4 2004 Instability of periodic solutions obtained by minimization. Zbl 1210.37042Ortega, Rafael 3 2004 The first 60 years of nonlinear analysis of Jean Mawhin. Papers from the conference, Sevilla, Spain, April 2003. Zbl 1064.35002Delgado, M. (ed.); López-Gómez, J. (ed.); Ortega, R. (ed.); Suárez, A. (ed.) 1 2004 Almost periodic upper and lower solutions. Zbl 1043.34046Ortega, Rafael; Tarallo, Massimo 14 2003 Differential equations with limit-periodic forcings. Zbl 1021.34015Alonso, Ana I.; Obaya, Rafael; Ortega, Rafael 9 2003 Almost periodic equations and conditions of Ambrosetti-Prodi type. Zbl 1055.34085Ortega, Rafael; Tarallo, Massimo 8 2003 Massera’s theorem for quasi-periodic differential equations. Zbl 1005.37021Ortega, Rafael; Tarallo, Massimo 10 2002 Periodic perturbations of an isochronous center. Zbl 1043.34049Ortega, Rafael 9 2002 Dynamics of a forced oscillator having an obstacle. Zbl 1054.34057Ortega, R. 9 2002 Periodic solutions of forced oscillators with several degrees of freedom. Zbl 1041.34003Ortega, Rafael; Sánchez, Luis A. 3 2002 A maximum principle for bounded solutions of the telegraph equation in space dimension three. Zbl 1002.35027Mawhin, Jean; Ortega, Rafael; Robles-Pérez, Aureliano M. 2 2002 Invariant curves of mappings with averaged small twist. Zbl 1136.37336Ortega, Rafael 20 2001 A duality theorem for periodic solutions of a class of second order evolution equations. Zbl 1010.34054Ortega, Rafael; Robles-Pérez, Aureliano M. 7 2001 Twist mappings, invariant curves and periodic differential equations. Zbl 1172.34326Ortega, Rafael 6 2001 A maximum principle for bounded solutions of the telegraph equations and applications to nonlinear forcings. Zbl 0972.35016Mawhin, Jean; Ortega, Rafael; Robles-Pérez, Aureliano M. 18 2000 Parabolic fixed points and stability criteria for nonlinear Hill’s equation. Zbl 0973.34046Núñez, Daniel; Ortega, Rafael 17 2000 Abstract competitive systems and orbital stability in \(\mathbb R^3\). Zbl 0951.34032Ortega, Rafael; Sánchez, Luis Ángel 13 2000 Non-continuation of the periodic oscillations of a forced pendulum in the presence of friction. Zbl 0970.34037Ortega, Rafael; Serra, Enrico; Tarallo, Massimo 9 2000 Counting periodic solutions of the forced pendulum equation. Zbl 0967.34037Ortega, Rafael 3 2000 Positively homogeneous equations in the plane. Zbl 1079.34011Fonda, Alessandro; Ortega, Rafael 3 2000 Degenerate equations of pendulum-type. Zbl 0958.34033Ortega, Rafael; Tarallo, Massimo 2 2000 Boundedness in a piecewise linear oscillator and a variant of the small twist theorem. Zbl 1030.34035Ortega, Rafael 55 1999 Bounded solutions of second order semilinear evolution equations and applications to the telegraph equation. Zbl 0927.34048Alonso, Jose Miguel; Mawhin, Jean; Ortega, Rafael 14 1999 Roots of unity and unbounded motions of an asymmetric oscillator. Zbl 0899.34023Alonso, José Miguel; Ortega, Rafael 46 1998 A maximum principle for periodic solutions of the telegraph equation. Zbl 0932.35016Ortega, Rafael; Robles-Pérez, Aureliano M. 27 1998 The number of stable periodic solutions of time-dependent Hamiltonian systems with one degree of freedom. Zbl 0946.34036Ortega, Rafael 10 1998 An exclusion principle for periodic competitive systems in three dimensions. Zbl 0901.34049Ortega, Rafael; Tineo, Antonio 9 1998 On Littlewood’s problem for the asymmetric oscillator. Zbl 1020.34032Ortega, Rafael 3 1998 Homeomorphisms of the disk with trivial dynamics and extinction of competitive systems. Zbl 0886.34025Campos, Juan; Ortega, Rafael; Tineo, Antonio 11 1997 A forced pendulum equation with many periodic solutions. Zbl 0899.34031Ortega, Rafael 7 1997 Nonexistence of invariant curves of mappings with small twist. Zbl 0907.58058Ortega, Rafael 2 1997 Asymmetric oscillators and twist mappings. Zbl 0860.34017Ortega, Rafael 61 1996 The periodic predator-prey Lotka-Volterra model. Zbl 0849.34026López-Gómez, Julián; Ortega, Rafael; Tineo, Antonio 33 1996 Unbounded solutions of semilinear equations at resonance. Zbl 0896.34026Alonso, José Miguel; Ortega, Rafael 32 1996 Periodic solutions of a Newtonian equation: Stability by the third approximation. Zbl 0855.34058Ortega, Rafael 30 1996 Resonance and non-resonance in a problem of boundedness. Zbl 0858.34018Ortega, Rafael; Tineo, Antonio 9 1996 A criterion for asymptotic stability based on topological degree. Zbl 0846.34056Ortega, Rafael 9 1996 Nonexistence of periodic solutions of a complex Riccati equation. Zbl 0842.34046Campos, Juan; Ortega, Rafael 9 1996 Some applications of the topological degree to stability theory. Zbl 0834.34058Ortega, Rafael 19 1995 Boundedness and global asymptotic stability of a forced oscillator. Zbl 0826.34043Alonso, Jose Miguel; Ortega, Rafael 13 1995 Global asymptotic stability of a forced Newtonian system with dissipation. Zbl 0844.34047Alonso, José Miguel; Ortega, Rafael 11 1995 On the number of positive periodic solutions for planar competing Lotka-Volterra systems. Zbl 0903.34037Ortega, Rafael; Tineo, Antonio 8 1995 On the spectrum of some linear noncooperative elliptic systems with radial symmetry. Zbl 0841.35031Dancer, E. N.; López-Gómez, J.; Ortega, R. 8 1995 A boundedness result of Landesman-Lazer type. Zbl 0817.34017Ortega, Rafael 6 1995 The stability of the equilibrium of a nonlinear Hill’s equation. Zbl 0807.34065Ortega, Rafael 34 1994 The index of Lyapunov stable fixed points in two dimensions. Zbl 0811.34018Dancer, E. N.; Ortega, R. 24 1994 A periodic prey-predator system. Zbl 0808.34043Amine, Zitan; Ortega, Rafael 21 1994 Existence of asymptotically stable periodic solutions of a forced equation of Liénard type. Zbl 0802.34050Zitan, Amine; Ortega, Rafael 12 1994 The twist coefficient of periodic solutions of a time-dependent Newton’s equation. Zbl 0761.34036Ortega, Rafael 17 1992 The first interval of stability of a periodic equation of Duffing type. Zbl 0757.34035Ortega, Rafael 13 1992 Critical growth for a superlinear elliptic problem in two dimensions. Zbl 0782.35023Ortega, Rafael 1 1992 Generic results for the existence of nondegenerate periodic solutions of some differential systems with periodic nonlinearities. Zbl 0742.34043Martinez-Amores, P.; Mawhin, J.; Ortega, R.; Willem, M. 8 1991 Topological degree and stability of periodic solutions for certain differential equations. Zbl 0677.34042Ortega, Rafael 16 1990 Stability of a periodic problem of Ambrosetti-Prodi type. Zbl 0724.34059Ortega, Rafael 10 1990 Nonexistence of radial solutions of two elliptic boundary value problems. Zbl 0721.35022Ortega, Rafael 4 1990 ...and 11 more Documents all cited Publications top 5 cited Publications all top 5 Cited by 613 Authors 45 Ortega, Rafael 25 Torres, Pedro José 18 Zhang, Meirong 17 Fonda, Alessandro 15 Obaya, Rafael 14 Liu, Bin 14 Yang, Xiaojing 13 Chu, Jifeng 12 Mawhin, Jean L. 11 An, Yukun 11 Campos, Juan 11 Li, Xiong 11 Tarallo, Massimo 11 Wang, Fanglei 11 Wang, Yiqian 10 Makarenkov, Oleg Yuryĭovych 10 Qian, Dingbian 10 Zanolin, Fabio 9 Andres, Jan 9 Boscaggin, Alberto 9 Nuñez, Daniel E. 9 Ureña, Antonio J. 8 Amster, Pablo 8 Gazzola, Filippo 8 Liu, Qihuai 8 Ruiz del Portal, Francisco Romero 8 Teng, Zhi-dong 8 Tineo, Antonio R. 7 Liang, Zaitao 7 López-Gómez, Julián 7 Sfecci, Andrea 7 Wang, Zhiguo 6 Chen, Lansun 6 Drábek, Pavel 6 Kunze, Markus 6 Piao, Daxiong 6 Rebelo, Carlota 5 Chen, Hongbin 5 Dambrosio, Walter 5 Essebbar, Brahim 5 Kannan, Rangachary 5 Krasnosel’skiĭ, Aleksandr Markovich 5 Llibre, Jaume 5 Marò, Stefano 5 Miguel-Alonso, Jose 5 Núñez, Carmen A. 5 Ruiz-Herrera, Alfonso 5 Wang, Feng 4 Cid, José Ángel 4 de la Llave, Rafael 4 Garrione, Maurizio 4 Jiang, Jifa 4 Jiang, Shunjun 4 Kokocki, Piotr 4 Kuo, Chungcheng 4 Langa, Jose’ Antonio 4 Lisena, Benedetta 4 Margheri, Alessandro 4 Mariani, Maria Cristina 4 Nieto Roig, Juan Jose 4 Novo, Sylvia 4 Rivera, Andrés M. 4 Robles-Pérez, Aureliano M. 4 Salazar, José Miguel 4 Sanchez, Luis Angel 4 Sanz, Ana M. 4 Shao, Jianying 4 Wang, Yi 4 Wang, Zaihong 3 Berchio, Elvise 3 Cañada Villar, Antonio 3 Cao, Junfei 3 Caraballo Garrido, Tomás 3 de Nápoli, Pablo Luis 3 Dehghan Takht Fooladi, Mehdi 3 Ezzinbi, Khalil 3 Fabry, Christian 3 Feltrin, Guglielmo 3 Holubová, Gabriela 3 Huang, Zaitang 3 Kamenskiĭ, Mikhaĭl Igor’evich 3 Korman, Philip L. 3 Leiva, Hugo 3 Li, Shengjun 3 Li, Yi 3 Li, Yongxiang 3 Liao, Fangfang 3 Lo, Kueiming 3 Ma, Shiwang 3 Meng, Gang 3 Nistri, Paolo 3 Niu, Lei 3 Omari, Pierpaolo 3 Peng, Yaqun 3 Pennequin, Denis 3 Rojas, David 3 Si, Jianguo 3 Sovrano, Elisa 3 Tajčová, Gabriela 3 Toader, Rodica ...and 513 more Authors all top 5 Cited in 136 Serials 86 Journal of Differential Equations 64 Journal of Mathematical Analysis and Applications 49 Nonlinear Analysis. 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Second Series 1 Tokyo Journal of Mathematics 1 Transactions of the Moscow Mathematical Society 1 Topology and its Applications ...and 36 more Serials all top 5 Cited in 38 Fields 445 Ordinary differential equations (34-XX) 186 Dynamical systems and ergodic theory (37-XX) 101 Partial differential equations (35-XX) 79 Operator theory (47-XX) 70 Biology and other natural sciences (92-XX) 61 Mechanics of particles and systems (70-XX) 20 Mechanics of deformable solids (74-XX) 16 Numerical analysis (65-XX) 15 Difference and functional equations (39-XX) 12 Abstract harmonic analysis (43-XX) 11 General topology (54-XX) 8 Harmonic analysis on Euclidean spaces (42-XX) 8 Probability theory and stochastic processes (60-XX) 6 Integral equations (45-XX) 6 Calculus of variations and optimal control; optimization (49-XX) 6 Global analysis, analysis on manifolds (58-XX) 6 Systems theory; control (93-XX) 5 Algebraic topology (55-XX) 4 Functions of a complex variable (30-XX) 4 Fluid mechanics (76-XX) 3 Real functions (26-XX) 3 Differential geometry (53-XX) 3 Optics, electromagnetic theory (78-XX) 3 Quantum theory (81-XX) 3 Statistical mechanics, structure of matter (82-XX) 2 Linear and multilinear algebra; matrix theory (15-XX) 2 Measure and integration (28-XX) 2 Functional analysis (46-XX) 2 Manifolds and cell complexes (57-XX) 2 Information and communication theory, circuits (94-XX) 1 Nonassociative rings and algebras (17-XX) 1 Potential theory (31-XX) 1 Several complex variables and analytic spaces (32-XX) 1 Approximations and expansions (41-XX) 1 Computer science (68-XX) 1 Relativity and gravitational theory (83-XX) 1 Astronomy and astrophysics (85-XX) 1 Operations research, mathematical programming (90-XX) Citations by Year