{"title":"群图上的芯片发射","authors":"Margaret Meyer, Dmitry Zakharov","doi":"10.1016/j.disc.2025.114631","DOIUrl":null,"url":null,"abstract":"<div><div>We define the Laplacian matrix and the Jacobian group of a finite graph of groups. We prove analogues of the matrix tree theorem and the class number formula for the order of the Jacobian of a graph of groups. Given a group <em>G</em> acting on a graph <em>X</em>, we define natural pushforward and pullback maps between the Jacobian groups of <em>X</em> and the quotient graph of groups <span><math><mi>X</mi><mo>/</mo><mo>/</mo><mi>G</mi></math></span>. For the case <span><math><mi>G</mi><mo>=</mo><mi>Z</mi><mo>/</mo><mn>2</mn><mi>Z</mi></math></span>, we also prove a combinatorial formula for the order of the kernel of the pushforward map.</div></div>","PeriodicalId":50572,"journal":{"name":"Discrete Mathematics","volume":"348 12","pages":"Article 114631"},"PeriodicalIF":0.7000,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Chip-firing on graphs of groups\",\"authors\":\"Margaret Meyer, Dmitry Zakharov\",\"doi\":\"10.1016/j.disc.2025.114631\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>We define the Laplacian matrix and the Jacobian group of a finite graph of groups. We prove analogues of the matrix tree theorem and the class number formula for the order of the Jacobian of a graph of groups. Given a group <em>G</em> acting on a graph <em>X</em>, we define natural pushforward and pullback maps between the Jacobian groups of <em>X</em> and the quotient graph of groups <span><math><mi>X</mi><mo>/</mo><mo>/</mo><mi>G</mi></math></span>. For the case <span><math><mi>G</mi><mo>=</mo><mi>Z</mi><mo>/</mo><mn>2</mn><mi>Z</mi></math></span>, we also prove a combinatorial formula for the order of the kernel of the pushforward map.</div></div>\",\"PeriodicalId\":50572,\"journal\":{\"name\":\"Discrete Mathematics\",\"volume\":\"348 12\",\"pages\":\"Article 114631\"},\"PeriodicalIF\":0.7000,\"publicationDate\":\"2025-06-12\",\"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/S0012365X25002390\",\"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/S0012365X25002390","RegionNum":3,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATHEMATICS","Score":null,"Total":0}
We define the Laplacian matrix and the Jacobian group of a finite graph of groups. We prove analogues of the matrix tree theorem and the class number formula for the order of the Jacobian of a graph of groups. Given a group G acting on a graph X, we define natural pushforward and pullback maps between the Jacobian groups of X and the quotient graph of groups . For the case , we also prove a combinatorial formula for the order of the kernel of the pushforward map.
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.