Krishna Hanumanthu, Cyril J. Jacob, B. N. Suhas, Amit Kumar Singh
{"title":"Hirzebruch曲面膨胀的Seshadri常数","authors":"Krishna Hanumanthu, Cyril J. Jacob, B. N. Suhas, Amit Kumar Singh","doi":"10.1002/mana.202400018","DOIUrl":null,"url":null,"abstract":"<p>Let <span></span><math>\n <semantics>\n <mrow>\n <mi>e</mi>\n <mo>,</mo>\n <mi>r</mi>\n <mo>≥</mo>\n <mn>0</mn>\n </mrow>\n <annotation>$e,r \\ge 0$</annotation>\n </semantics></math> be integers and let <span></span><math>\n <semantics>\n <mrow>\n <msub>\n <mi>F</mi>\n <mi>e</mi>\n </msub>\n <mo>:</mo>\n <mo>=</mo>\n <mi>P</mi>\n <mrow>\n <mo>(</mo>\n <msub>\n <mi>O</mi>\n <msup>\n <mi>P</mi>\n <mn>1</mn>\n </msup>\n </msub>\n <mi>⊕</mi>\n <msub>\n <mi>O</mi>\n <msup>\n <mi>P</mi>\n <mn>1</mn>\n </msup>\n </msub>\n <mrow>\n <mo>(</mo>\n <mo>−</mo>\n <mi>e</mi>\n <mo>)</mo>\n </mrow>\n <mo>)</mo>\n </mrow>\n </mrow>\n <annotation>$\\mathbb {F}_e: = \\mathbb {P}(\\mathcal {O}_{\\mathbb {P}^1} \\oplus \\mathcal {O}_{\\mathbb {P}^1}(-e))$</annotation>\n </semantics></math> denote the Hirzebruch surface with invariant <span></span><math>\n <semantics>\n <mi>e</mi>\n <annotation>$e$</annotation>\n </semantics></math>. We compute the Seshadri constants of an ample line bundle at an arbitrary point of the <span></span><math>\n <semantics>\n <mi>r</mi>\n <annotation>$r$</annotation>\n </semantics></math>-point blow-up of <span></span><math>\n <semantics>\n <msub>\n <mi>F</mi>\n <mi>e</mi>\n </msub>\n <annotation>$\\mathbb {F}_e$</annotation>\n </semantics></math> when <span></span><math>\n <semantics>\n <mrow>\n <mi>r</mi>\n <mo>≤</mo>\n <mi>e</mi>\n <mo>−</mo>\n <mn>1</mn>\n </mrow>\n <annotation>$r \\le e-1$</annotation>\n </semantics></math> and at a very general point when <span></span><math>\n <semantics>\n <mrow>\n <mi>r</mi>\n <mo>=</mo>\n <mi>e</mi>\n </mrow>\n <annotation>$r=e$</annotation>\n </semantics></math> or <span></span><math>\n <semantics>\n <mrow>\n <mi>r</mi>\n <mo>=</mo>\n <mi>e</mi>\n <mo>+</mo>\n <mn>1</mn>\n </mrow>\n <annotation>$r=e+1$</annotation>\n </semantics></math>. We also discuss several conjectures on linear systems of curves on the blow-up of <span></span><math>\n <semantics>\n <msub>\n <mi>F</mi>\n <mi>e</mi>\n </msub>\n <annotation>$\\mathbb {F}_e$</annotation>\n </semantics></math> at <span></span><math>\n <semantics>\n <mi>r</mi>\n <annotation>$r$</annotation>\n </semantics></math> very general points.</p>","PeriodicalId":49853,"journal":{"name":"Mathematische Nachrichten","volume":"298 2","pages":"437-455"},"PeriodicalIF":0.8000,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Seshadri constants on blow-ups of Hirzebruch surfaces\",\"authors\":\"Krishna Hanumanthu, Cyril J. Jacob, B. N. Suhas, Amit Kumar Singh\",\"doi\":\"10.1002/mana.202400018\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<p>Let <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>e</mi>\\n <mo>,</mo>\\n <mi>r</mi>\\n <mo>≥</mo>\\n <mn>0</mn>\\n </mrow>\\n <annotation>$e,r \\\\ge 0$</annotation>\\n </semantics></math> be integers and let <span></span><math>\\n <semantics>\\n <mrow>\\n <msub>\\n <mi>F</mi>\\n <mi>e</mi>\\n </msub>\\n <mo>:</mo>\\n <mo>=</mo>\\n <mi>P</mi>\\n <mrow>\\n <mo>(</mo>\\n <msub>\\n <mi>O</mi>\\n <msup>\\n <mi>P</mi>\\n <mn>1</mn>\\n </msup>\\n </msub>\\n <mi>⊕</mi>\\n <msub>\\n <mi>O</mi>\\n <msup>\\n <mi>P</mi>\\n <mn>1</mn>\\n </msup>\\n </msub>\\n <mrow>\\n <mo>(</mo>\\n <mo>−</mo>\\n <mi>e</mi>\\n <mo>)</mo>\\n </mrow>\\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n <annotation>$\\\\mathbb {F}_e: = \\\\mathbb {P}(\\\\mathcal {O}_{\\\\mathbb {P}^1} \\\\oplus \\\\mathcal {O}_{\\\\mathbb {P}^1}(-e))$</annotation>\\n </semantics></math> denote the Hirzebruch surface with invariant <span></span><math>\\n <semantics>\\n <mi>e</mi>\\n <annotation>$e$</annotation>\\n </semantics></math>. We compute the Seshadri constants of an ample line bundle at an arbitrary point of the <span></span><math>\\n <semantics>\\n <mi>r</mi>\\n <annotation>$r$</annotation>\\n </semantics></math>-point blow-up of <span></span><math>\\n <semantics>\\n <msub>\\n <mi>F</mi>\\n <mi>e</mi>\\n </msub>\\n <annotation>$\\\\mathbb {F}_e$</annotation>\\n </semantics></math> when <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>r</mi>\\n <mo>≤</mo>\\n <mi>e</mi>\\n <mo>−</mo>\\n <mn>1</mn>\\n </mrow>\\n <annotation>$r \\\\le e-1$</annotation>\\n </semantics></math> and at a very general point when <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>r</mi>\\n <mo>=</mo>\\n <mi>e</mi>\\n </mrow>\\n <annotation>$r=e$</annotation>\\n </semantics></math> or <span></span><math>\\n <semantics>\\n <mrow>\\n <mi>r</mi>\\n <mo>=</mo>\\n <mi>e</mi>\\n <mo>+</mo>\\n <mn>1</mn>\\n </mrow>\\n <annotation>$r=e+1$</annotation>\\n </semantics></math>. We also discuss several conjectures on linear systems of curves on the blow-up of <span></span><math>\\n <semantics>\\n <msub>\\n <mi>F</mi>\\n <mi>e</mi>\\n </msub>\\n <annotation>$\\\\mathbb {F}_e$</annotation>\\n </semantics></math> at <span></span><math>\\n <semantics>\\n <mi>r</mi>\\n <annotation>$r$</annotation>\\n </semantics></math> very general points.</p>\",\"PeriodicalId\":49853,\"journal\":{\"name\":\"Mathematische Nachrichten\",\"volume\":\"298 2\",\"pages\":\"437-455\"},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2024-11-14\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Mathematische Nachrichten\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1002/mana.202400018\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Mathematische Nachrichten","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/mana.202400018","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Seshadri constants on blow-ups of Hirzebruch surfaces
Let be integers and let denote the Hirzebruch surface with invariant . We compute the Seshadri constants of an ample line bundle at an arbitrary point of the -point blow-up of when and at a very general point when or . We also discuss several conjectures on linear systems of curves on the blow-up of at very general points.
期刊介绍:
Mathematische Nachrichten - Mathematical News publishes original papers on new results and methods that hold prospect for substantial progress in mathematics and its applications. All branches of analysis, algebra, number theory, geometry and topology, flow mechanics and theoretical aspects of stochastics are given special emphasis. Mathematische Nachrichten is indexed/abstracted in Current Contents/Physical, Chemical and Earth Sciences; Mathematical Review; Zentralblatt für Mathematik; Math Database on STN International, INSPEC; Science Citation Index