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Special Issue: Celebrating the 75th Birthday of V.V. Kozlov (Issue Editors: Sergey Bolotin, Vladimir Dragović, and Dmitry Treschev)
Functional Invariants in Semilocal Bifurcations
Yulij S. Ilyashenkoab a IUM,
per. Bolshoy Vlasyevskiy 11, 119002 Moscow, Russia
b HSE University,
ul. Myasnitskaya 20, 101000 Moscow, Russia
Abstract:
In [7] an open set of structurally unstable families of vector fields on a sphere was
constructed. More precisely, a vector field with a degeneracy of codimension three was discovered
whose bifurcation in a generic three-parameter family has a numeric invariant. This vector field
has a polycycle and two saddles, one inside and one outside this polycycle; one separatrix of
the outside saddle winds towards the polycycle and one separatrix of the inside saddle winds
from it. Families with functional invariants were constructed also. In [2] a hyperbolic polycycle
with five vertices and no saddles outside it was constructed whose bifurcations in its arbitrary
narrow neighborhood (semilocal bifurcations in other words) have a numeric invariant and thus
are structurally unstable. This paper deals with semilocal bifurcations. A hyperbolic polycycle
with nine edges is constructed whose semilocal bifurcation in an open set of nine-parameter
families has a functional invariant.
Keywords:
polycycles, semilocal bifurcations, functional invariants
Received: 13.05.2025 Accepted: 10.07.2025
Citation:
Yulij S. Ilyashenko, “Functional Invariants in Semilocal Bifurcations”, Regul. Chaotic Dyn., 30:4 (2025), 618–627
Linking options:
https://www.mathnet.ru/eng/rcd1325 https://www.mathnet.ru/eng/rcd/v30/i4/p618
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