{ "id": "2402.08759", "version": "v2", "published": "2024-02-13T19:52:41.000Z", "updated": "2024-09-21T01:30:51.000Z", "title": "Spectral instability of peakons for the $b$-family of Novikov equations", "authors": [ "Xijun Deng", "Stéphane Lafortune" ], "comment": "19 pages, no figure", "categories": [ "math.AP", "nlin.SI" ], "abstract": "In this paper, we are concerned with a one-parameter family of peakon equations with cubic nonlinearity parametrized by a parameter usually denoted by the letter $b$. This family is called the ``$b$-Novikov'' since it reduces to the integrable Novikov equation in the case $b=3$. By extending the corresponding linearized operator defined on functions in $H^1(\\mathbb{R})$ to one defined on weaker functions on $L^2(\\mathbb{R})$, we prove spectral and linear instability on $L^2(\\mathbb{R})$ of peakons in the $b$-Novikov equations for any $b$. We also consider the stability on $H^1(\\mathbb{R})$ and show that the peakons are spectrally or linearly stable only in the case $b=3$.", "revisions": [ { "version": "v2", "updated": "2024-09-21T01:30:51.000Z" } ], "analyses": { "subjects": [ "35B35", "35C08", "35P05", "35Q35" ], "keywords": [ "spectral instability", "cubic nonlinearity", "integrable novikov equation", "peakon equations", "weaker functions" ], "note": { "typesetting": "TeX", "pages": 19, "language": "en", "license": "arXiv", "status": "editable" } } }