{"title":"关于具有线性秩的多面体与分裂闭合的广义性","authors":"Sanjeeb Dash , Yatharth Dubey","doi":"10.1016/j.disopt.2023.100821","DOIUrl":null,"url":null,"abstract":"<div><p><span>In this paper we study the rank of polytopes contained in the 0-1 cube with respect to </span><span><math><mi>t</mi></math></span>-branch split cuts and <span><math><mi>t</mi></math></span>-dimensional lattice cuts for a fixed positive integer <span><math><mi>t</mi></math></span>. These inequalities are the same as split cuts when <span><math><mrow><mi>t</mi><mo>=</mo><mn>1</mn></mrow></math></span> and generalize split cuts when <span><math><mrow><mi>t</mi><mo>></mo><mn>1</mn></mrow></math></span>. For polytopes contained in the <span><math><mi>n</mi></math></span>-dimensional 0-1 cube, the work of Balas implies that the split rank can be at most <span><math><mi>n</mi></math></span>, and this bound is tight as Cornuéjols and Li gave an example with split rank <span><math><mi>n</mi></math></span>. All known examples with high split rank – i.e., at least <span><math><mrow><mi>c</mi><mi>n</mi></mrow></math></span> for some positive constant <span><math><mrow><mi>c</mi><mo><</mo><mn>1</mn></mrow></math></span> – are defined by exponentially many (as a function of <span><math><mi>n</mi></math></span><span>) linear inequalities. For any fixed integer </span><span><math><mrow><mi>t</mi><mo>></mo><mn>0</mn></mrow></math></span>, we give a family of polytopes contained in <span><math><msup><mrow><mrow><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></mrow></mrow><mrow><mi>n</mi></mrow></msup></math></span> for sufficiently large <span><math><mi>n</mi></math></span> such that each polytope has empty integer hull, is defined by <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span> inequalities, and has rank <span><math><mrow><mi>Ω</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span> with respect to <span><math><mi>t</mi></math></span>-dimensional lattice cuts. Therefore the split rank of these polytopes is <span><math><mrow><mi>Ω</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span><span><span>. It was shown earlier that there exist generalized branch-and-bound proofs, with logarithmic depth, of the nonexistence of </span>integer points in these polytopes. Therefore, our lower bound results on split rank show an exponential separation between the depth of branch-and-bound proofs and split rank.</span></p></div>","PeriodicalId":50571,"journal":{"name":"Discrete Optimization","volume":"51 ","pages":"Article 100821"},"PeriodicalIF":0.9000,"publicationDate":"2024-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"On polytopes with linear rank with respect to generalizations of the split closure\",\"authors\":\"Sanjeeb Dash , Yatharth Dubey\",\"doi\":\"10.1016/j.disopt.2023.100821\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p><span>In this paper we study the rank of polytopes contained in the 0-1 cube with respect to </span><span><math><mi>t</mi></math></span>-branch split cuts and <span><math><mi>t</mi></math></span>-dimensional lattice cuts for a fixed positive integer <span><math><mi>t</mi></math></span>. These inequalities are the same as split cuts when <span><math><mrow><mi>t</mi><mo>=</mo><mn>1</mn></mrow></math></span> and generalize split cuts when <span><math><mrow><mi>t</mi><mo>></mo><mn>1</mn></mrow></math></span>. For polytopes contained in the <span><math><mi>n</mi></math></span>-dimensional 0-1 cube, the work of Balas implies that the split rank can be at most <span><math><mi>n</mi></math></span>, and this bound is tight as Cornuéjols and Li gave an example with split rank <span><math><mi>n</mi></math></span>. All known examples with high split rank – i.e., at least <span><math><mrow><mi>c</mi><mi>n</mi></mrow></math></span> for some positive constant <span><math><mrow><mi>c</mi><mo><</mo><mn>1</mn></mrow></math></span> – are defined by exponentially many (as a function of <span><math><mi>n</mi></math></span><span>) linear inequalities. For any fixed integer </span><span><math><mrow><mi>t</mi><mo>></mo><mn>0</mn></mrow></math></span>, we give a family of polytopes contained in <span><math><msup><mrow><mrow><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></mrow></mrow><mrow><mi>n</mi></mrow></msup></math></span> for sufficiently large <span><math><mi>n</mi></math></span> such that each polytope has empty integer hull, is defined by <span><math><mrow><mi>O</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span> inequalities, and has rank <span><math><mrow><mi>Ω</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span> with respect to <span><math><mi>t</mi></math></span>-dimensional lattice cuts. Therefore the split rank of these polytopes is <span><math><mrow><mi>Ω</mi><mrow><mo>(</mo><mi>n</mi><mo>)</mo></mrow></mrow></math></span><span><span>. It was shown earlier that there exist generalized branch-and-bound proofs, with logarithmic depth, of the nonexistence of </span>integer points in these polytopes. Therefore, our lower bound results on split rank show an exponential separation between the depth of branch-and-bound proofs and split rank.</span></p></div>\",\"PeriodicalId\":50571,\"journal\":{\"name\":\"Discrete Optimization\",\"volume\":\"51 \",\"pages\":\"Article 100821\"},\"PeriodicalIF\":0.9000,\"publicationDate\":\"2024-01-18\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Discrete Optimization\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1572528623000634\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS, APPLIED\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Discrete Optimization","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1572528623000634","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS, APPLIED","Score":null,"Total":0}
引用次数: 0
摘要
本文研究了在固定正整数 t 条件下,0-1 立方体中包含的多边形的秩与 t 分支分裂切割和 t 维网格切割的关系。这些不等式与 t=1 时的分裂切割相同,并概括了 t>1 时的分裂切割。对于包含在 n 维 0-1 立方体中的多边形,巴拉斯的研究意味着分裂秩最多为 n,而且这个约束很严格,因为科内霍尔斯和李给出了一个分裂秩为 n 的例子、对于某个正常数 c<1,至少为 cn - 是由指数级数量(作为 n 的函数)的线性不等式定义的。对于任意固定整数 t>0,我们给出了一个包含在足够大 n 的 [0,1]n 中的多面体族,使得每个多面体都具有空整数簇,由 O(n) 个不等式定义,并且相对于 t 维网格切分具有秩 Ω(n)。因此,这些多面体的分裂秩为 Ω(n)。前面已经证明,这些多面体中不存在整数点,存在深度为对数的广义分支和约束证明。因此,我们关于分裂等级的下界结果表明,分支约束证明的深度与分裂等级之间存在指数级的分离。
On polytopes with linear rank with respect to generalizations of the split closure
In this paper we study the rank of polytopes contained in the 0-1 cube with respect to -branch split cuts and -dimensional lattice cuts for a fixed positive integer . These inequalities are the same as split cuts when and generalize split cuts when . For polytopes contained in the -dimensional 0-1 cube, the work of Balas implies that the split rank can be at most , and this bound is tight as Cornuéjols and Li gave an example with split rank . All known examples with high split rank – i.e., at least for some positive constant – are defined by exponentially many (as a function of ) linear inequalities. For any fixed integer , we give a family of polytopes contained in for sufficiently large such that each polytope has empty integer hull, is defined by inequalities, and has rank with respect to -dimensional lattice cuts. Therefore the split rank of these polytopes is . It was shown earlier that there exist generalized branch-and-bound proofs, with logarithmic depth, of the nonexistence of integer points in these polytopes. Therefore, our lower bound results on split rank show an exponential separation between the depth of branch-and-bound proofs and split rank.
期刊介绍:
Discrete Optimization publishes research papers on the mathematical, computational and applied aspects of all areas of integer programming and combinatorial optimization. In addition to reports on mathematical results pertinent to discrete optimization, the journal welcomes submissions on algorithmic developments, computational experiments, and novel applications (in particular, large-scale and real-time applications). The journal also publishes clearly labelled surveys, reviews, short notes, and open problems. Manuscripts submitted for possible publication to Discrete Optimization should report on original research, should not have been previously published, and should not be under consideration for publication by any other journal.