{"title":"Sharp Lower Estimations for Invariants Associated with the Ideal of Antiderivatives of Singularities","authors":"","doi":"10.1007/s41980-024-00866-z","DOIUrl":null,"url":null,"abstract":"<h3>Abstract</h3> <p>Let (<em>V</em>, 0) be a hypersurface with an isolated singularity at the origin defined by the holomorphic function <span> <span>\\(f: (\\mathbb {C}^n, 0)\\rightarrow (\\mathbb {C}, 0)\\)</span> </span>. We introduce a new derivation Lie algebra associated to (<em>V</em>, 0). The new Lie algebra is defined by the ideal of antiderivatives with respect to the Tjurina ideal of (<em>V</em>, 0). More precisely, let <span> <span>\\(I = (f, \\frac{\\partial f}{\\partial x_1},\\ldots , \\frac{\\partial f}{\\partial x_n})\\)</span> </span> and <span> <span>\\(\\Delta (I):= \\{g\\mid g,\\frac{\\partial g}{\\partial x_1},\\ldots , \\frac{\\partial g}{\\partial x_n}\\in I\\}\\)</span> </span>, then <span> <span>\\(A^\\Delta (V):= \\mathcal O_n/\\Delta (I)\\)</span> </span> and <span> <span>\\(L^\\Delta (V):= \\textrm{Der}(A^\\Delta (V),A^\\Delta (V))\\)</span> </span>. Their dimensions as a complex vector space are denoted as <span> <span>\\(\\beta (V)\\)</span> </span> and <span> <span>\\(\\delta (V)\\)</span> </span>, respectively. <span> <span>\\(\\delta (V)\\)</span> </span> is a new invariant of singularities. In this paper we study the new local algebra <span> <span>\\(A^\\Delta (V)\\)</span> </span> and the derivation Lie algebra <span> <span>\\(L^\\Delta (V)\\)</span> </span>, and also compute them for fewnomial isolated singularities. Moreover, we formulate sharp lower estimation conjectures for <span> <span>\\(\\beta (V)\\)</span> </span> and <span> <span>\\(\\delta (V)\\)</span> </span> when (<em>V</em>, 0) are weighted homogeneous isolated hypersurface singularities. We verify these conjectures for a large class of singularities. Lastly, we provide an application of <span> <span>\\(\\beta (V)\\)</span> </span> and <span> <span>\\(\\delta (V)\\)</span> </span> to distinguishing contact classes of singularities.</p>","PeriodicalId":9395,"journal":{"name":"Bulletin of The Iranian Mathematical Society","volume":null,"pages":null},"PeriodicalIF":0.7000,"publicationDate":"2024-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Bulletin of The Iranian Mathematical Society","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1007/s41980-024-00866-z","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
Abstract
Let (V, 0) be a hypersurface with an isolated singularity at the origin defined by the holomorphic function \(f: (\mathbb {C}^n, 0)\rightarrow (\mathbb {C}, 0)\). We introduce a new derivation Lie algebra associated to (V, 0). The new Lie algebra is defined by the ideal of antiderivatives with respect to the Tjurina ideal of (V, 0). More precisely, let \(I = (f, \frac{\partial f}{\partial x_1},\ldots , \frac{\partial f}{\partial x_n})\) and \(\Delta (I):= \{g\mid g,\frac{\partial g}{\partial x_1},\ldots , \frac{\partial g}{\partial x_n}\in I\}\), then \(A^\Delta (V):= \mathcal O_n/\Delta (I)\) and \(L^\Delta (V):= \textrm{Der}(A^\Delta (V),A^\Delta (V))\). Their dimensions as a complex vector space are denoted as \(\beta (V)\) and \(\delta (V)\), respectively. \(\delta (V)\) is a new invariant of singularities. In this paper we study the new local algebra \(A^\Delta (V)\) and the derivation Lie algebra \(L^\Delta (V)\), and also compute them for fewnomial isolated singularities. Moreover, we formulate sharp lower estimation conjectures for \(\beta (V)\) and \(\delta (V)\) when (V, 0) are weighted homogeneous isolated hypersurface singularities. We verify these conjectures for a large class of singularities. Lastly, we provide an application of \(\beta (V)\) and \(\delta (V)\) to distinguishing contact classes of singularities.
期刊介绍:
The Bulletin of the Iranian Mathematical Society (BIMS) publishes original research papers as well as survey articles on a variety of hot topics from distinguished mathematicians. Research papers presented comprise of innovative contributions while expository survey articles feature important results that appeal to a broad audience. Articles are expected to address active research topics and are required to cite existing (including recent) relevant literature appropriately. Papers are critically reviewed on the basis of quality in its exposition, brevity, potential applications, motivation, value and originality of the results. The BIMS takes a high standard policy against any type plagiarism. The editorial board is devoted to solicit expert referees for a fast and unbiased review process.