Abstract
We discuss various definitions of equivalence for bifurcations of vector fields on the sphere and give a large number of examples (both known and new) that illustrate the advantages and disadvantages of different definitions. In addition to the classical definitions of strong and weak equivalence, we consider new notions of Sing-equivalence and moderate equivalence. These definitions seem to be more relevant to and consistent with the intuitive notion of equivalent bifurcations. They were introduced and used to describe the structural instability of some finite-parameter families of vector fields on the sphere and to study invariants of their classification.
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Notes
B. L. Shleifman, “Topology of deformations of complex parabolic germs” (in preparation).
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Funding
This work was supported by the HSE Laboratory of Dynamical Systems and Applications (under grant 075-15-2019-1931 of the Ministry of Science and Higher Education of the Russian Federation) and by the Russian Foundation for Basic Research (project no. 20-01-00420).
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Goncharuk, N.B., Ilyashenko, Y.S. Various Equivalence Relations in Global Bifurcation Theory. Proc. Steklov Inst. Math. 310, 78–97 (2020). https://doi.org/10.1134/S0081543820050065
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DOI: https://doi.org/10.1134/S0081543820050065