$C^1$-Smooth Skew Products on a $3D$-Torus Which Have an $\Omega$-Stable Quotient and Continuous Itinerary Auxiliary Multifunctions

    Received 08 January 2026; accepted 02 March 2026; published 09 April 2026


    Author(s): Efremova L. S.

    This work is devoted to the description of some set in the space of $C^1$-smooth skew products of circle maps that have a $3D$-torus as phase space and possess periodic points. This set of maps consists of skew products with an $\Omega$-stable quotient, continuous itinerary auxiliary multifunctions and contains, in particular, an open, but not dense (in the distinguished set) subset of $\Omega$-stable maps (with respect to $C^1$-smooth perturbations of skew products class).
    We also select here the other set of $C^1$-smooth skew products of circle maps such that $C^1$-smooth $\Omega$-stable skew products form an everywhere dense subset of this set.
    Much attention is paid to maps of the second selected set admitting a maximal ``prickly'' attractor, which is presented as the union of a $2D$-torus with a family of arcs of various lengths, orthogonal to the above $2D$-torus and originating from points of an everywhere dense set of continuum cardinality on this $2D$-torus.
    Keywords: skew product of circle maps, itinerary auxiliary functions, $\Omega$-function, maximal attractor, degree of a circle map, $C^1$- $\Omega$-stability
    Citation: Efremova L. S.,  $C^1$-Smooth Skew Products on a $3D$-Torus Which Have an $\Omega$-Stable Quotient and Continuous Itinerary Auxiliary Multifunctions, Rus. J. Nonlin. Dyn., 2026 https://doi.org/10.20537/nd260401
    DOI:10.20537/nd260401


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