{"title":"Collatz高周期不存在","authors":"Kevin Knight","doi":"10.1016/j.disc.2025.114812","DOIUrl":null,"url":null,"abstract":"<div><div>The Collatz function takes odd <em>n</em> to <span><math><mo>(</mo><mn>3</mn><mi>n</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>/</mo><mn>2</mn></math></span> and even <em>n</em> to <span><math><mi>n</mi><mo>/</mo><mn>2</mn></math></span>. Under the iterated Collatz function, every positive integer is conjectured to end up in the trivial cycle 1-2-1. Two types of rational Collatz cycles are of special interest. Consider the set <span><math><mi>S</mi><mo>(</mo><mi>k</mi><mo>,</mo><mi>x</mi><mo>)</mo></math></span> consisting of the smallest members of <em>k</em>-length cycles with <em>x</em> odd terms. The <em>circuit</em> contains the smallest member of <span><math><mi>S</mi><mo>(</mo><mi>k</mi><mo>,</mo><mi>x</mi><mo>)</mo></math></span>, while the <em>high cycle</em> contains the largest. It is known that no circuits of positive integers exist (except 1-2-1); this paper shows that there are likewise no high cycles of positive integers.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":"349 3","pages":"Article 114812"},"PeriodicalIF":0.7000,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Collatz high cycles do not exist\",\"authors\":\"Kevin Knight\",\"doi\":\"10.1016/j.disc.2025.114812\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The Collatz function takes odd <em>n</em> to <span><math><mo>(</mo><mn>3</mn><mi>n</mi><mo>+</mo><mn>1</mn><mo>)</mo><mo>/</mo><mn>2</mn></math></span> and even <em>n</em> to <span><math><mi>n</mi><mo>/</mo><mn>2</mn></math></span>. Under the iterated Collatz function, every positive integer is conjectured to end up in the trivial cycle 1-2-1. Two types of rational Collatz cycles are of special interest. Consider the set <span><math><mi>S</mi><mo>(</mo><mi>k</mi><mo>,</mo><mi>x</mi><mo>)</mo></math></span> consisting of the smallest members of <em>k</em>-length cycles with <em>x</em> odd terms. The <em>circuit</em> contains the smallest member of <span><math><mi>S</mi><mo>(</mo><mi>k</mi><mo>,</mo><mi>x</mi><mo>)</mo></math></span>, while the <em>high cycle</em> contains the largest. It is known that no circuits of positive integers exist (except 1-2-1); this paper shows that there are likewise no high cycles of positive integers.</div></div>\",\"PeriodicalId\":50572,\"journal\":{\"name\":\"Discrete Mathematics\",\"volume\":\"349 3\",\"pages\":\"Article 114812\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-09-23\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Discrete Mathematics\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0012365X25004200\",\"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":"Discrete Mathematics","FirstCategoryId":"100","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0012365X25004200","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
The Collatz function takes odd n to and even n to . Under the iterated Collatz function, every positive integer is conjectured to end up in the trivial cycle 1-2-1. Two types of rational Collatz cycles are of special interest. Consider the set consisting of the smallest members of k-length cycles with x odd terms. The circuit contains the smallest member of , while the high cycle contains the largest. It is known that no circuits of positive integers exist (except 1-2-1); this paper shows that there are likewise no high cycles of positive integers.
期刊介绍:
Discrete Mathematics provides a common forum for significant research in many areas of discrete mathematics and combinatorics. Among the fields covered by Discrete Mathematics are graph and hypergraph theory, enumeration, coding theory, block designs, the combinatorics of partially ordered sets, extremal set theory, matroid theory, algebraic combinatorics, discrete geometry, matrices, and discrete probability theory.
Items in the journal include research articles (Contributions or Notes, depending on length) and survey/expository articles (Perspectives). Efforts are made to process the submission of Notes (short articles) quickly. The Perspectives section features expository articles accessible to a broad audience that cast new light or present unifying points of view on well-known or insufficiently-known topics.