{"title":"余维四环的自由分辨率和Lefschetz性质","authors":"Nancy Abdallah , Hal Schenck","doi":"10.1016/j.jsc.2023.102257","DOIUrl":null,"url":null,"abstract":"<div><p>In (<span>Stanley, 1978</span>), Stanley constructs an example of an Artinian Gorenstein (AG) ring <em>A</em> with non-unimodal <em>H</em>-vector <span><math><mo>(</mo><mn>1</mn><mo>,</mo><mn>13</mn><mo>,</mo><mn>12</mn><mo>,</mo><mn>13</mn><mo>,</mo><mn>1</mn><mo>)</mo></math></span>. Migliore-Zanello show in (<span>Migliore and Zanello, 2017</span>) that for regularity <span><math><mi>r</mi><mo>=</mo><mn>4</mn></math></span><span>, Stanley's example has the smallest possible codimension </span><em>c</em> for an AG ring with non-unimodal <em>H</em>-vector.</p><p>The weak Lefschetz property (WLP) has been much studied for AG rings; it is easy to show that an AG ring with non-unimodal <em>H</em>-vector fails to have WLP. In codimension <span><math><mi>c</mi><mo>=</mo><mn>3</mn></math></span> it is conjectured that all AG rings have WLP. For <span><math><mi>c</mi><mo>=</mo><mn>4</mn></math></span>, Gondim shows in (<span>Gondim, 2017</span>) that WLP always holds for <span><math><mi>r</mi><mo>≤</mo><mn>4</mn></math></span> and gives a family where WLP fails for any <span><math><mi>r</mi><mo>≥</mo><mn>7</mn></math></span>, building on Ikeda's example (<span>Ikeda, 1996</span>) of failure for <span><math><mi>r</mi><mo>=</mo><mn>5</mn></math></span>. In this note we study the minimal free resolution of <em>A</em> and relation to Lefschetz properties (both weak and strong) and Jordan type for <span><math><mi>c</mi><mo>=</mo><mn>4</mn></math></span> and <span><math><mi>r</mi><mo>≤</mo><mn>6</mn></math></span>.</p></div>","PeriodicalId":0,"journal":{"name":"","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"7","resultStr":"{\"title\":\"Free resolutions and Lefschetz properties of some Artin Gorenstein rings of codimension four\",\"authors\":\"Nancy Abdallah , Hal Schenck\",\"doi\":\"10.1016/j.jsc.2023.102257\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>In (<span>Stanley, 1978</span>), Stanley constructs an example of an Artinian Gorenstein (AG) ring <em>A</em> with non-unimodal <em>H</em>-vector <span><math><mo>(</mo><mn>1</mn><mo>,</mo><mn>13</mn><mo>,</mo><mn>12</mn><mo>,</mo><mn>13</mn><mo>,</mo><mn>1</mn><mo>)</mo></math></span>. Migliore-Zanello show in (<span>Migliore and Zanello, 2017</span>) that for regularity <span><math><mi>r</mi><mo>=</mo><mn>4</mn></math></span><span>, Stanley's example has the smallest possible codimension </span><em>c</em> for an AG ring with non-unimodal <em>H</em>-vector.</p><p>The weak Lefschetz property (WLP) has been much studied for AG rings; it is easy to show that an AG ring with non-unimodal <em>H</em>-vector fails to have WLP. In codimension <span><math><mi>c</mi><mo>=</mo><mn>3</mn></math></span> it is conjectured that all AG rings have WLP. For <span><math><mi>c</mi><mo>=</mo><mn>4</mn></math></span>, Gondim shows in (<span>Gondim, 2017</span>) that WLP always holds for <span><math><mi>r</mi><mo>≤</mo><mn>4</mn></math></span> and gives a family where WLP fails for any <span><math><mi>r</mi><mo>≥</mo><mn>7</mn></math></span>, building on Ikeda's example (<span>Ikeda, 1996</span>) of failure for <span><math><mi>r</mi><mo>=</mo><mn>5</mn></math></span>. In this note we study the minimal free resolution of <em>A</em> and relation to Lefschetz properties (both weak and strong) and Jordan type for <span><math><mi>c</mi><mo>=</mo><mn>4</mn></math></span> and <span><math><mi>r</mi><mo>≤</mo><mn>6</mn></math></span>.</p></div>\",\"PeriodicalId\":0,\"journal\":{\"name\":\"\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0,\"publicationDate\":\"2023-08-21\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"7\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0747717123000718\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0747717123000718","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 7
摘要
在(Stanley,1978)中,Stanley构造了具有非单峰H-向量(1,13,12,13,1)的Artinian-Gorenstein(AG)环A的一个例子。Migliore Zanello在(Migliore and Zanello,2017)中证明,对于正则性r=4,Stanley的例子对于具有非单峰H-向量的AG环具有最小可能余维数c;很容易证明具有非单峰H-向量的AG环不具有WLP。在余维c=3中,推测所有的AG环都具有WLP。对于c=4,Gondim在(Gondim,2017)中表明,对于r≤4,WLP总是成立的,并基于Ikeda关于r=5的失败的例子(Ikeda,1996)给出了一个WLP对于任何r≥7失败的族。在本文中,我们研究了当c=4和r≤6时,A的最小自由分辨率以及与Lefschetz性质(弱和强)和Jordan型的关系。
Free resolutions and Lefschetz properties of some Artin Gorenstein rings of codimension four
In (Stanley, 1978), Stanley constructs an example of an Artinian Gorenstein (AG) ring A with non-unimodal H-vector . Migliore-Zanello show in (Migliore and Zanello, 2017) that for regularity , Stanley's example has the smallest possible codimension c for an AG ring with non-unimodal H-vector.
The weak Lefschetz property (WLP) has been much studied for AG rings; it is easy to show that an AG ring with non-unimodal H-vector fails to have WLP. In codimension it is conjectured that all AG rings have WLP. For , Gondim shows in (Gondim, 2017) that WLP always holds for and gives a family where WLP fails for any , building on Ikeda's example (Ikeda, 1996) of failure for . In this note we study the minimal free resolution of A and relation to Lefschetz properties (both weak and strong) and Jordan type for and .