{"title":"关于一些有理生成函数的定理和猜想","authors":"Richard P. Stanley","doi":"10.1016/j.ejc.2023.103814","DOIUrl":null,"url":null,"abstract":"<div><p>Let <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> denote the <span><math><mi>i</mi></math></span>th Fibonacci number, and define <span><math><mrow><msubsup><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>n</mi></mrow></msubsup><mfenced><mrow><mn>1</mn><mo>+</mo></mrow></mfenced><mfenced><mrow><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>F</mi></mrow><mrow><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub></mrow></msup></mrow></mfenced><mo>=</mo><msub><mrow><mo>∑</mo></mrow><mrow><mi>k</mi></mrow></msub><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow><msup><mrow><mi>x</mi></mrow><mrow><mi>k</mi></mrow></msup></mrow></math></span>. The paper is concerned primarily with the coefficients <span><math><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow></mrow></math></span>. In particular, for any <span><math><mrow><mi>r</mi><mo>≥</mo><mn>0</mn></mrow></math></span> the generating function <span><math><mrow><msub><mrow><mo>∑</mo></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub><mrow><mo>(</mo><msub><mrow><mo>∑</mo></mrow><mrow><mi>k</mi></mrow></msub><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><msup><mrow><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow></mrow><mrow><mi>r</mi></mrow></msup><mo>)</mo></mrow><msup><mrow><mi>x</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></math></span> is rational. The coefficients <span><math><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow></mrow></math></span> can be displayed in an array called the <span><em>Fibonacci triangle </em><em>poset</em></span> <span><math><mi>F</mi></math></span><span> with some interesting further properties, including an encoding of a certain dense linear order on the nonnegative integers. Some generalizations are briefly considered, but there remain many open questions.</span></p></div>","PeriodicalId":50490,"journal":{"name":"European Journal of Combinatorics","volume":null,"pages":null},"PeriodicalIF":1.0000,"publicationDate":"2024-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Theorems and conjectures on some rational generating functions\",\"authors\":\"Richard P. Stanley\",\"doi\":\"10.1016/j.ejc.2023.103814\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Let <span><math><msub><mrow><mi>F</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> denote the <span><math><mi>i</mi></math></span>th Fibonacci number, and define <span><math><mrow><msubsup><mrow><mo>∏</mo></mrow><mrow><mi>i</mi><mo>=</mo><mn>1</mn></mrow><mrow><mi>n</mi></mrow></msubsup><mfenced><mrow><mn>1</mn><mo>+</mo></mrow></mfenced><mfenced><mrow><msup><mrow><mi>x</mi></mrow><mrow><msub><mrow><mi>F</mi></mrow><mrow><mi>i</mi><mo>+</mo><mn>1</mn></mrow></msub></mrow></msup></mrow></mfenced><mo>=</mo><msub><mrow><mo>∑</mo></mrow><mrow><mi>k</mi></mrow></msub><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow><msup><mrow><mi>x</mi></mrow><mrow><mi>k</mi></mrow></msup></mrow></math></span>. The paper is concerned primarily with the coefficients <span><math><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow></mrow></math></span>. In particular, for any <span><math><mrow><mi>r</mi><mo>≥</mo><mn>0</mn></mrow></math></span> the generating function <span><math><mrow><msub><mrow><mo>∑</mo></mrow><mrow><mi>n</mi><mo>≥</mo><mn>0</mn></mrow></msub><mrow><mo>(</mo><msub><mrow><mo>∑</mo></mrow><mrow><mi>k</mi></mrow></msub><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><msup><mrow><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow></mrow><mrow><mi>r</mi></mrow></msup><mo>)</mo></mrow><msup><mrow><mi>x</mi></mrow><mrow><mi>n</mi></mrow></msup></mrow></math></span> is rational. The coefficients <span><math><mrow><msub><mrow><mi>c</mi></mrow><mrow><mi>n</mi></mrow></msub><mrow><mo>(</mo><mi>k</mi><mo>)</mo></mrow></mrow></math></span> can be displayed in an array called the <span><em>Fibonacci triangle </em><em>poset</em></span> <span><math><mi>F</mi></math></span><span> with some interesting further properties, including an encoding of a certain dense linear order on the nonnegative integers. Some generalizations are briefly considered, but there remain many open questions.</span></p></div>\",\"PeriodicalId\":50490,\"journal\":{\"name\":\"European Journal of Combinatorics\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2024-06-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"European Journal of Combinatorics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0195669823001312\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"European Journal of Combinatorics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0195669823001312","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MATHEMATICS","Score":null,"Total":0}
引用次数: 0
摘要
让 Fi 表示第 i 个斐波那契数,并定义∏i=1n1+xFi+1=∑kcn(k)xk。本文主要关注 cn(k) 的系数。特别是,对于任意 r≥0 的生成函数 ∑n≥0(∑kcn(k)r)xn 是有理的。cn(k)系数可以显示在一个叫做斐波那契三角形正集 F 的数组中,它还具有一些有趣的性质,包括对非负整数的某种密集线性阶的编码。本文简要讨论了一些概括性问题,但仍有许多悬而未决的问题。
Theorems and conjectures on some rational generating functions
Let denote the th Fibonacci number, and define . The paper is concerned primarily with the coefficients . In particular, for any the generating function is rational. The coefficients can be displayed in an array called the Fibonacci triangle poset with some interesting further properties, including an encoding of a certain dense linear order on the nonnegative integers. Some generalizations are briefly considered, but there remain many open questions.
期刊介绍:
The European Journal of Combinatorics is a high standard, international, bimonthly journal of pure mathematics, specializing in theories arising from combinatorial problems. The journal is primarily open to papers dealing with mathematical structures within combinatorics and/or establishing direct links between combinatorics and other branches of mathematics and the theories of computing. The journal includes full-length research papers on important topics.