{"title":"图的id因子临界和分数因子[a,b]的距离谱条件","authors":"Tingyan Ma , Ligong Wang","doi":"10.1016/j.disc.2025.114803","DOIUrl":null,"url":null,"abstract":"<div><div>Let <span><math><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>,</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>)</mo></math></span> be a graph with vertex set <span><math><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> and edge set <span><math><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span>. A graph is <em>ID</em>-factor-critical if for every independent set <em>I</em> of <em>G</em> whose size has the same parity as <span><math><mo>|</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></math></span>, <span><math><mi>G</mi><mo>−</mo><mi>I</mi></math></span> has a perfect matching. For two positive integers <em>a</em> and <em>b</em> with <span><math><mi>a</mi><mo>≤</mo><mi>b</mi></math></span>, let <em>h</em>: <span><math><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>→</mo><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></math></span> be a function on <span><math><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> satisfying <span><math><mi>a</mi><mo>≤</mo><msub><mrow><mo>∑</mo></mrow><mrow><mi>e</mi><mo>∈</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow></msub><mi>h</mi><mo>(</mo><mi>e</mi><mo>)</mo><mo>≤</mo><mi>b</mi></math></span> for any vertex <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>∈</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span>. Then the spanning subgraph with edge set <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>h</mi></mrow></msub></math></span>, denoted by <span><math><mi>G</mi><mo>[</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>h</mi></mrow></msub><mo>]</mo></math></span>, is called a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-factor of <em>G</em> with indicator function <em>h</em>, where <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>h</mi></mrow></msub><mo>=</mo><mo>{</mo><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo><mi>h</mi><mo>(</mo><mi>e</mi><mo>)</mo><mo>></mo><mn>0</mn><mo>}</mo></math></span> and <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo><mo>=</mo><mo>{</mo><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo><mi>e</mi></math></span> is incident with <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> in <em>G</em>}. A graph is defined as a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-deleted graph if for any <span><math><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span>, <span><math><mi>G</mi><mo>−</mo><mi>e</mi></math></span> contains a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-factor. For any integer <span><math><mi>k</mi><mo>≥</mo><mn>1</mn></math></span>, a graph has a <em>k</em>-factor if it contains a <em>k</em>-regular spanning subgraph. In this paper, we firstly give a distance spectral radius condition of <em>G</em> to guarantee that <em>G</em> is <em>ID</em>-factor-critical. Furthermore, we provide sufficient conditions in terms of distance spectral radius and distance signless Laplacian spectral radius for a graph to contain a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-factor, fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-deleted-factor and <em>k</em>-factor.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":"349 3","pages":"Article 114803"},"PeriodicalIF":0.7000,"publicationDate":"2025-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Distance spectral conditions for ID-factor-criticality and fractional [a,b]-factor of graphs\",\"authors\":\"Tingyan Ma , Ligong Wang\",\"doi\":\"10.1016/j.disc.2025.114803\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>Let <span><math><mi>G</mi><mo>=</mo><mo>(</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>,</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>)</mo></math></span> be a graph with vertex set <span><math><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> and edge set <span><math><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span>. A graph is <em>ID</em>-factor-critical if for every independent set <em>I</em> of <em>G</em> whose size has the same parity as <span><math><mo>|</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo></math></span>, <span><math><mi>G</mi><mo>−</mo><mi>I</mi></math></span> has a perfect matching. For two positive integers <em>a</em> and <em>b</em> with <span><math><mi>a</mi><mo>≤</mo><mi>b</mi></math></span>, let <em>h</em>: <span><math><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>→</mo><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></math></span> be a function on <span><math><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span> satisfying <span><math><mi>a</mi><mo>≤</mo><msub><mrow><mo>∑</mo></mrow><mrow><mi>e</mi><mo>∈</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo></mrow></msub><mi>h</mi><mo>(</mo><mi>e</mi><mo>)</mo><mo>≤</mo><mi>b</mi></math></span> for any vertex <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>∈</mo><mi>V</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span>. Then the spanning subgraph with edge set <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>h</mi></mrow></msub></math></span>, denoted by <span><math><mi>G</mi><mo>[</mo><msub><mrow><mi>E</mi></mrow><mrow><mi>h</mi></mrow></msub><mo>]</mo></math></span>, is called a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-factor of <em>G</em> with indicator function <em>h</em>, where <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>h</mi></mrow></msub><mo>=</mo><mo>{</mo><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo><mi>h</mi><mo>(</mo><mi>e</mi><mo>)</mo><mo>></mo><mn>0</mn><mo>}</mo></math></span> and <span><math><msub><mrow><mi>E</mi></mrow><mrow><mi>G</mi></mrow></msub><mo>(</mo><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub><mo>)</mo><mo>=</mo><mo>{</mo><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo><mo>|</mo><mi>e</mi></math></span> is incident with <span><math><msub><mrow><mi>v</mi></mrow><mrow><mi>i</mi></mrow></msub></math></span> in <em>G</em>}. A graph is defined as a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-deleted graph if for any <span><math><mi>e</mi><mo>∈</mo><mi>E</mi><mo>(</mo><mi>G</mi><mo>)</mo></math></span>, <span><math><mi>G</mi><mo>−</mo><mi>e</mi></math></span> contains a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-factor. For any integer <span><math><mi>k</mi><mo>≥</mo><mn>1</mn></math></span>, a graph has a <em>k</em>-factor if it contains a <em>k</em>-regular spanning subgraph. In this paper, we firstly give a distance spectral radius condition of <em>G</em> to guarantee that <em>G</em> is <em>ID</em>-factor-critical. Furthermore, we provide sufficient conditions in terms of distance spectral radius and distance signless Laplacian spectral radius for a graph to contain a fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-factor, fractional <span><math><mo>[</mo><mi>a</mi><mo>,</mo><mi>b</mi><mo>]</mo></math></span>-deleted-factor and <em>k</em>-factor.</div></div>\",\"PeriodicalId\":50572,\"journal\":{\"name\":\"Discrete Mathematics\",\"volume\":\"349 3\",\"pages\":\"Article 114803\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-09-22\",\"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/S0012365X2500411X\",\"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/S0012365X2500411X","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
Distance spectral conditions for ID-factor-criticality and fractional [a,b]-factor of graphs
Let be a graph with vertex set and edge set . A graph is ID-factor-critical if for every independent set I of G whose size has the same parity as , has a perfect matching. For two positive integers a and b with , let h: be a function on satisfying for any vertex . Then the spanning subgraph with edge set , denoted by , is called a fractional -factor of G with indicator function h, where and is incident with in G}. A graph is defined as a fractional -deleted graph if for any , contains a fractional -factor. For any integer , a graph has a k-factor if it contains a k-regular spanning subgraph. In this paper, we firstly give a distance spectral radius condition of G to guarantee that G is ID-factor-critical. Furthermore, we provide sufficient conditions in terms of distance spectral radius and distance signless Laplacian spectral radius for a graph to contain a fractional -factor, fractional -deleted-factor and k-factor.
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.