{ "id": "2208.10115", "version": "v1", "published": "2022-08-22T07:40:58.000Z", "updated": "2022-08-22T07:40:58.000Z", "title": "Invariant tori for area-preserving maps with ultra-differentiable perturbation and Liouvillean frequency", "authors": [ "Hongyu Cheng", "Shimin Wang", "Fenfen Wang" ], "categories": [ "math.DS" ], "abstract": "We prove the existence of invariant tori to the area-preserving maps defined on $ \\mathbb{R}^2\\times\\mathbb{T} $ \\begin{equation*} \\bar{x}=F(x,\\theta), \\qquad \\bar{\\theta}=\\theta+\\alpha\\, \\,(\\alpha\\in \\mathbb{R}\\setminus\\mathbb{Q}), \\end{equation*} where $ F $ is closed to a linear rotation, and the perturbation is ultra-differentiable in $ \\theta\\in \\mathbb{T},$ which is very closed to $C^{\\infty}$ regularity. Moreover, we assume that the frequency $\\alpha$ is any irrational number without other arithmetic conditions and the smallness of the perturbation does not depend on $\\alpha$. Thus, both the difficulties from the ultra-differentiability of the perturbation and Liouvillean frequency will appear in this work. The proof of the main result is based on the Kolmogorov-Arnold-Moser (KAM) scheme about the area-preserving maps with some new techniques.", "revisions": [ { "version": "v1", "updated": "2022-08-22T07:40:58.000Z" } ], "analyses": { "keywords": [ "area-preserving maps", "invariant tori", "liouvillean frequency", "ultra-differentiable perturbation", "linear rotation" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }