{"title":"Gröbner基和Krull维的Lovász-Saks-Sherijver理想关联到一棵树上","authors":"Mohammad Farrokhi D. G. , Ali Akbar Yazdan Pour","doi":"10.1016/j.jalgebra.2025.03.049","DOIUrl":null,"url":null,"abstract":"<div><div>Let <span><math><mi>K</mi></math></span> be a field and <em>n</em> be a positive integer. Let <span><math><mi>Γ</mi><mo>=</mo><mo>(</mo><mo>[</mo><mi>n</mi><mo>]</mo><mo>,</mo><mi>E</mi><mo>)</mo></math></span> be a simple graph, where <span><math><mo>[</mo><mi>n</mi><mo>]</mo><mo>=</mo><mo>{</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mi>n</mi><mo>}</mo></math></span>. If <span><math><mi>S</mi><mo>=</mo><mi>K</mi><mo>[</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>,</mo><msub><mrow><mi>y</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>y</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>]</mo></math></span> is a polynomial ring, then the graded ideal<span><span><span><math><msubsup><mrow><mi>L</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mi>K</mi></mrow></msubsup><mo>(</mo><mn>2</mn><mo>)</mo><mo>=</mo><mrow><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>x</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>+</mo><msub><mrow><mi>y</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>y</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>:</mo><mspace></mspace><mo>{</mo><mi>i</mi><mo>,</mo><mi>j</mi><mo>}</mo><mo>∈</mo><mi>E</mi><mo>(</mo><mi>Γ</mi><mo>)</mo><mo>)</mo></mrow><mo>⊂</mo><mi>S</mi><mo>,</mo></math></span></span></span> is called the Lovász-Saks-Schrijver ideal, LSS-ideal for short, of Γ with respect to <span><math><mi>K</mi></math></span>. In the present paper, we compute a Gröbner basis of this ideal with respect to lexicographic ordering induced by <span><math><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>></mo><mo>⋯</mo><mo>></mo><msub><mrow><mi>x</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>></mo><msub><mrow><mi>y</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>></mo><mo>⋯</mo><mo>></mo><msub><mrow><mi>y</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> when <span><math><mi>Γ</mi><mo>=</mo><mi>T</mi></math></span> is a tree. As a result, we show that it is independent of the choice of the ground field <span><math><mi>K</mi></math></span> and compute the Hilbert series of <span><math><msubsup><mrow><mi>L</mi></mrow><mrow><mi>T</mi></mrow><mrow><mi>K</mi></mrow></msubsup><mo>(</mo><mn>2</mn><mo>)</mo></math></span>. Finally, we present concrete combinatorial formulas to obtain the Krull dimension of <span><math><mi>S</mi><mo>/</mo><msubsup><mrow><mi>L</mi></mrow><mrow><mi>T</mi></mrow><mrow><mi>K</mi></mrow></msubsup><mo>(</mo><mn>2</mn><mo>)</mo></math></span> as well as lower and upper bounds for Krull dimension.</div></div>","PeriodicalId":14888,"journal":{"name":"Journal of Algebra","volume":"678 ","pages":"Pages 224-252"},"PeriodicalIF":0.8000,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Gröbner basis and Krull dimension of the Lovász-Saks-Sherijver ideal associated to a tree\",\"authors\":\"Mohammad Farrokhi D. G. , Ali Akbar Yazdan Pour\",\"doi\":\"10.1016/j.jalgebra.2025.03.049\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Let <span><math><mi>K</mi></math></span> be a field and <em>n</em> be a positive integer. Let <span><math><mi>Γ</mi><mo>=</mo><mo>(</mo><mo>[</mo><mi>n</mi><mo>]</mo><mo>,</mo><mi>E</mi><mo>)</mo></math></span> be a simple graph, where <span><math><mo>[</mo><mi>n</mi><mo>]</mo><mo>=</mo><mo>{</mo><mn>1</mn><mo>,</mo><mo>…</mo><mo>,</mo><mi>n</mi><mo>}</mo></math></span>. If <span><math><mi>S</mi><mo>=</mo><mi>K</mi><mo>[</mo><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>,</mo><msub><mrow><mi>y</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>,</mo><mo>…</mo><mo>,</mo><msub><mrow><mi>y</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>]</mo></math></span> is a polynomial ring, then the graded ideal<span><span><span><math><msubsup><mrow><mi>L</mi></mrow><mrow><mi>Γ</mi></mrow><mrow><mi>K</mi></mrow></msubsup><mo>(</mo><mn>2</mn><mo>)</mo><mo>=</mo><mrow><mo>(</mo><msub><mrow><mi>x</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>x</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>+</mo><msub><mrow><mi>y</mi></mrow><mrow><mi>i</mi></mrow></msub><msub><mrow><mi>y</mi></mrow><mrow><mi>j</mi></mrow></msub><mo>:</mo><mspace></mspace><mo>{</mo><mi>i</mi><mo>,</mo><mi>j</mi><mo>}</mo><mo>∈</mo><mi>E</mi><mo>(</mo><mi>Γ</mi><mo>)</mo><mo>)</mo></mrow><mo>⊂</mo><mi>S</mi><mo>,</mo></math></span></span></span> is called the Lovász-Saks-Schrijver ideal, LSS-ideal for short, of Γ with respect to <span><math><mi>K</mi></math></span>. In the present paper, we compute a Gröbner basis of this ideal with respect to lexicographic ordering induced by <span><math><msub><mrow><mi>x</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>></mo><mo>⋯</mo><mo>></mo><msub><mrow><mi>x</mi></mrow><mrow><mi>n</mi></mrow></msub><mo>></mo><msub><mrow><mi>y</mi></mrow><mrow><mn>1</mn></mrow></msub><mo>></mo><mo>⋯</mo><mo>></mo><msub><mrow><mi>y</mi></mrow><mrow><mi>n</mi></mrow></msub></math></span> when <span><math><mi>Γ</mi><mo>=</mo><mi>T</mi></math></span> is a tree. As a result, we show that it is independent of the choice of the ground field <span><math><mi>K</mi></math></span> and compute the Hilbert series of <span><math><msubsup><mrow><mi>L</mi></mrow><mrow><mi>T</mi></mrow><mrow><mi>K</mi></mrow></msubsup><mo>(</mo><mn>2</mn><mo>)</mo></math></span>. Finally, we present concrete combinatorial formulas to obtain the Krull dimension of <span><math><mi>S</mi><mo>/</mo><msubsup><mrow><mi>L</mi></mrow><mrow><mi>T</mi></mrow><mrow><mi>K</mi></mrow></msubsup><mo>(</mo><mn>2</mn><mo>)</mo></math></span> as well as lower and upper bounds for Krull dimension.</div></div>\",\"PeriodicalId\":14888,\"journal\":{\"name\":\"Journal of Algebra\",\"volume\":\"678 \",\"pages\":\"Pages 224-252\"},\"PeriodicalIF\":0.8000,\"publicationDate\":\"2025-04-16\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Algebra\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0021869325002066\",\"RegionNum\":2,\"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":"Journal of Algebra","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0021869325002066","RegionNum":2,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Gröbner basis and Krull dimension of the Lovász-Saks-Sherijver ideal associated to a tree
Let be a field and n be a positive integer. Let be a simple graph, where . If is a polynomial ring, then the graded ideal is called the Lovász-Saks-Schrijver ideal, LSS-ideal for short, of Γ with respect to . In the present paper, we compute a Gröbner basis of this ideal with respect to lexicographic ordering induced by when is a tree. As a result, we show that it is independent of the choice of the ground field and compute the Hilbert series of . Finally, we present concrete combinatorial formulas to obtain the Krull dimension of as well as lower and upper bounds for Krull dimension.
期刊介绍:
The Journal of Algebra is a leading international journal and publishes papers that demonstrate high quality research results in algebra and related computational aspects. Only the very best and most interesting papers are to be considered for publication in the journal. With this in mind, it is important that the contribution offer a substantial result that will have a lasting effect upon the field. The journal also seeks work that presents innovative techniques that offer promising results for future research.