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{"title":"关于Alon-Tarsi最短周期覆盖猜想的注记","authors":"Yilun Luo, Rong-Xia Hao, Rong Luo, Cun-Quan Zhang","doi":"10.1002/jgt.70026","DOIUrl":null,"url":null,"abstract":"<div>\n \n <p>The shortest cycle cover conjecture (SCC conjecture), proposed by Alon and Tarsi, asserts that every bridgeless cubic graph <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>G</mi>\n </mrow>\n </mrow>\n </semantics></math> has a cycle cover with a total length at most <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mfrac>\n <mn>21</mn>\n \n <mn>15</mn>\n </mfrac>\n \n <mo>∣</mo>\n \n <mi>E</mi>\n \n <mrow>\n <mo>(</mo>\n \n <mi>G</mi>\n \n <mo>)</mo>\n </mrow>\n \n <mo>∣</mo>\n </mrow>\n </mrow>\n </semantics></math>. Tarsi further proposed a related conjecture, the <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <msub>\n <mi>SCC</mi>\n \n <mn>3</mn>\n </msub>\n </mrow>\n </mrow>\n </semantics></math> conjecture, which states that every bridgeless cubic graph <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>G</mi>\n </mrow>\n </mrow>\n </semantics></math> has a 3-cycle cover with a total length at most <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mfrac>\n <mn>22</mn>\n \n <mn>15</mn>\n </mfrac>\n \n <mo>∣</mo>\n \n <mi>E</mi>\n \n <mrow>\n <mo>(</mo>\n \n <mi>G</mi>\n \n <mo>)</mo>\n </mrow>\n \n <mo>∣</mo>\n </mrow>\n </mrow>\n </semantics></math>. In this paper, we prove that every cyclically odd-<span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mrow>\n <mo>(</mo>\n \n <mrow>\n <mn>4</mn>\n \n <mi>k</mi>\n \n <mo>+</mo>\n \n <mn>1</mn>\n </mrow>\n \n <mo>)</mo>\n </mrow>\n </mrow>\n </mrow>\n </semantics></math>-edge-connected cubic graph <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>G</mi>\n </mrow>\n </mrow>\n </semantics></math> has a 3-cycle cover with a total length at most <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mfrac>\n <mn>20</mn>\n \n <mn>15</mn>\n </mfrac>\n \n <mo>∣</mo>\n \n <mi>E</mi>\n \n <mrow>\n <mo>(</mo>\n \n <mi>G</mi>\n \n <mo>)</mo>\n </mrow>\n \n <mo>∣</mo>\n \n <mo>+</mo>\n \n <mfrac>\n <mn>1</mn>\n \n <mrow>\n <mn>2</mn>\n \n <mi>k</mi>\n \n <mo>+</mo>\n \n <mn>1</mn>\n </mrow>\n </mfrac>\n \n <mo>∣</mo>\n \n <mi>E</mi>\n \n <mrow>\n <mo>(</mo>\n \n <mi>G</mi>\n \n <mo>)</mo>\n </mrow>\n \n <mo>∣</mo>\n </mrow>\n </mrow>\n </semantics></math>. Consequently, the SCC conjecture and the <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <msub>\n <mi>SCC</mi>\n \n <mn>3</mn>\n </msub>\n </mrow>\n </mrow>\n </semantics></math> conjecture are verified in this paper for cubic graphs with cyclic odd-edge-connectivity at least 29 and 17, respectively. Additionally, for cubic graphs that satisfies Kaiser–Raspaud conjecture (i.e., every bridgeless cubic graph has two perfect matchings <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <msub>\n <mi>M</mi>\n \n <mn>1</mn>\n </msub>\n </mrow>\n </mrow>\n </semantics></math> and <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <msub>\n <mi>M</mi>\n \n <mn>2</mn>\n </msub>\n </mrow>\n </mrow>\n </semantics></math> and a parity subgraph <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <mi>J</mi>\n </mrow>\n </mrow>\n </semantics></math>, such that <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <msub>\n <mi>M</mi>\n \n <mn>1</mn>\n </msub>\n \n <mo>∩</mo>\n \n <msub>\n <mi>M</mi>\n \n <mn>2</mn>\n </msub>\n \n <mo>∩</mo>\n \n <mi>J</mi>\n \n <mo>=</mo>\n \n <mo>∅</mo>\n </mrow>\n </mrow>\n </semantics></math>), the SCC conjecture and the <span></span><math>\n <semantics>\n <mrow>\n \n <mrow>\n <msub>\n <mi>SCC</mi>\n \n <mn>3</mn>\n </msub>\n </mrow>\n </mrow>\n </semantics></math> conjecture are verified for graphs with girth at least 20 and 10, respectively.</p>\n </div>","PeriodicalId":16014,"journal":{"name":"Journal of Graph Theory","volume":"112 2","pages":"172-177"},"PeriodicalIF":1.0000,"publicationDate":"2026-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"A Note on Alon–Tarsi Shortest Cycle Cover Conjecture\",\"authors\":\"Yilun Luo, Rong-Xia Hao, Rong Luo, Cun-Quan Zhang\",\"doi\":\"10.1002/jgt.70026\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div>\\n \\n <p>The shortest cycle cover conjecture (SCC conjecture), proposed by Alon and Tarsi, asserts that every bridgeless cubic graph <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mi>G</mi>\\n </mrow>\\n </mrow>\\n </semantics></math> has a cycle cover with a total length at most <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mfrac>\\n <mn>21</mn>\\n \\n <mn>15</mn>\\n </mfrac>\\n \\n <mo>∣</mo>\\n \\n <mi>E</mi>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mi>G</mi>\\n \\n <mo>)</mo>\\n </mrow>\\n \\n <mo>∣</mo>\\n </mrow>\\n </mrow>\\n </semantics></math>. Tarsi further proposed a related conjecture, the <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <msub>\\n <mi>SCC</mi>\\n \\n <mn>3</mn>\\n </msub>\\n </mrow>\\n </mrow>\\n </semantics></math> conjecture, which states that every bridgeless cubic graph <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mi>G</mi>\\n </mrow>\\n </mrow>\\n </semantics></math> has a 3-cycle cover with a total length at most <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mfrac>\\n <mn>22</mn>\\n \\n <mn>15</mn>\\n </mfrac>\\n \\n <mo>∣</mo>\\n \\n <mi>E</mi>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mi>G</mi>\\n \\n <mo>)</mo>\\n </mrow>\\n \\n <mo>∣</mo>\\n </mrow>\\n </mrow>\\n </semantics></math>. In this paper, we prove that every cyclically odd-<span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mrow>\\n <mo>(</mo>\\n \\n <mrow>\\n <mn>4</mn>\\n \\n <mi>k</mi>\\n \\n <mo>+</mo>\\n \\n <mn>1</mn>\\n </mrow>\\n \\n <mo>)</mo>\\n </mrow>\\n </mrow>\\n </mrow>\\n </semantics></math>-edge-connected cubic graph <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mi>G</mi>\\n </mrow>\\n </mrow>\\n </semantics></math> has a 3-cycle cover with a total length at most <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mfrac>\\n <mn>20</mn>\\n \\n <mn>15</mn>\\n </mfrac>\\n \\n <mo>∣</mo>\\n \\n <mi>E</mi>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mi>G</mi>\\n \\n <mo>)</mo>\\n </mrow>\\n \\n <mo>∣</mo>\\n \\n <mo>+</mo>\\n \\n <mfrac>\\n <mn>1</mn>\\n \\n <mrow>\\n <mn>2</mn>\\n \\n <mi>k</mi>\\n \\n <mo>+</mo>\\n \\n <mn>1</mn>\\n </mrow>\\n </mfrac>\\n \\n <mo>∣</mo>\\n \\n <mi>E</mi>\\n \\n <mrow>\\n <mo>(</mo>\\n \\n <mi>G</mi>\\n \\n <mo>)</mo>\\n </mrow>\\n \\n <mo>∣</mo>\\n </mrow>\\n </mrow>\\n </semantics></math>. Consequently, the SCC conjecture and the <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <msub>\\n <mi>SCC</mi>\\n \\n <mn>3</mn>\\n </msub>\\n </mrow>\\n </mrow>\\n </semantics></math> conjecture are verified in this paper for cubic graphs with cyclic odd-edge-connectivity at least 29 and 17, respectively. Additionally, for cubic graphs that satisfies Kaiser–Raspaud conjecture (i.e., every bridgeless cubic graph has two perfect matchings <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <msub>\\n <mi>M</mi>\\n \\n <mn>1</mn>\\n </msub>\\n </mrow>\\n </mrow>\\n </semantics></math> and <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <msub>\\n <mi>M</mi>\\n \\n <mn>2</mn>\\n </msub>\\n </mrow>\\n </mrow>\\n </semantics></math> and a parity subgraph <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <mi>J</mi>\\n </mrow>\\n </mrow>\\n </semantics></math>, such that <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <msub>\\n <mi>M</mi>\\n \\n <mn>1</mn>\\n </msub>\\n \\n <mo>∩</mo>\\n \\n <msub>\\n <mi>M</mi>\\n \\n <mn>2</mn>\\n </msub>\\n \\n <mo>∩</mo>\\n \\n <mi>J</mi>\\n \\n <mo>=</mo>\\n \\n <mo>∅</mo>\\n </mrow>\\n </mrow>\\n </semantics></math>), the SCC conjecture and the <span></span><math>\\n <semantics>\\n <mrow>\\n \\n <mrow>\\n <msub>\\n <mi>SCC</mi>\\n \\n <mn>3</mn>\\n </msub>\\n </mrow>\\n </mrow>\\n </semantics></math> conjecture are verified for graphs with girth at least 20 and 10, respectively.</p>\\n </div>\",\"PeriodicalId\":16014,\"journal\":{\"name\":\"Journal of Graph Theory\",\"volume\":\"112 2\",\"pages\":\"172-177\"},\"PeriodicalIF\":1.0000,\"publicationDate\":\"2026-04-13\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Graph Theory\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://onlinelibrary.wiley.com/doi/10.1002/jgt.70026\",\"RegionNum\":3,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"2026/3/20 0:00:00\",\"PubModel\":\"Epub\",\"JCR\":\"Q2\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Graph Theory","FirstCategoryId":"100","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/jgt.70026","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"2026/3/20 0:00:00","PubModel":"Epub","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
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