@article{10272/21685, year = {2022}, url = {https://hdl.handle.net/10272/21685}, abstract = {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 eigenvalue with geometric multiplicity two) and two Hopf bifurcations. We focus on the more complex case in which the doublezero degeneracy organizes several codimension-one singularities, namely transcritical, pitchfork, Hopf and heteroclinic bifurcations. The analysis of the normal form of a Hopf-transcritical bifurcation allows to obtain the expressions for the corresponding bifurcation curves. A degenerate double-zero bifurcation is also considered. The theoretical information obtained is very helpful to start a numerical study of the 3D system. Thus, the presence of degenerate heteroclinic and homoclinic orbits, T-point heteroclinic loops and chaotic attractors is detected. We find numerical evidence that, at least, four curves of codimension-two global bifurcations are related to the triple-zero degeneracy in the system analyzed.}, organization = {We thank the reviewers for their careful reading of the manuscript and their very constructive remarks which have helped a lot to improve the presentation of the results. This work has been partially supported by the Ministerio de Economia y Competitividad, Spain (project MTM2017-87915-C2-1-P, co-financed with FEDER funds) , by the Ministerio de Ciencia, Innovacion y Universidades, Spain (project PGC2018-096265-B-I00, co-financed with FEDER funds) and by the Consejeria de Economia, Innovacion, Ciencia y Empleo de la Junta de Andalucia, Spain (FQM-276, TIC-0130, UHU-1260150 and P20_01160) .}, publisher = {Elsevier}, title = {Double-zero degeneracy and heteroclinic cycles in a perturbation of the Lorenz system}, doi = {10.1016/j.cnsns.2022.106482}, author = {Algaba Durán, Antonio and Domínguez Moreno, María Cinta and Merino Morlesín, Manuel and Rodríguez Luis, Alejandro José}, }