{"title":"在整个过程中最低限度的行为","authors":"Jakob Hofstad","doi":"10.1017/s0963548324000105","DOIUrl":null,"url":null,"abstract":"The <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline2.png\" /> <jats:tex-math> $d$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>-process generates a graph at random by starting with an empty graph with <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline3.png\" /> <jats:tex-math> $n$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> vertices, then adding edges one at a time uniformly at random among all pairs of vertices which have degrees at most <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline4.png\" /> <jats:tex-math> $d-1$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> and are not mutually joined. We show that, in the evolution of a random graph with <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline5.png\" /> <jats:tex-math> $n$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> vertices under the <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline6.png\" /> <jats:tex-math> $d$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>-process with <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline7.png\" /> <jats:tex-math> $d$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> fixed, with high probability, for each <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline8.png\" /> <jats:tex-math> $j \\in \\{0,1,\\dots,d-2\\}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>, the minimum degree jumps from <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline9.png\" /> <jats:tex-math> $j$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> to <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline10.png\" /> <jats:tex-math> $j+1$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> when the number of steps left is on the order of <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline11.png\" /> <jats:tex-math> $\\ln (n)^{d-j-1}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>. This answers a question of Ruciński and Wormald. More specifically, we show that, when the last vertex of degree <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline12.png\" /> <jats:tex-math> $j$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> disappears, the number of steps left divided by <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline13.png\" /> <jats:tex-math> $\\ln (n)^{d-j-1}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> converges in distribution to the exponential random variable of mean <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline14.png\" /> <jats:tex-math> $\\frac{j!}{2(d-1)!}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>; furthermore, these <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\"http://www.w3.org/1999/xlink\" mime-subtype=\"png\" xlink:href=\"S0963548324000105_inline15.png\" /> <jats:tex-math> $d-1$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> distributions are independent.","PeriodicalId":10503,"journal":{"name":"Combinatorics, Probability and Computing","volume":null,"pages":null},"PeriodicalIF":0.0000,"publicationDate":"2024-04-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Behaviour of the minimum degree throughout the -process\",\"authors\":\"Jakob Hofstad\",\"doi\":\"10.1017/s0963548324000105\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"The <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline2.png\\\" /> <jats:tex-math> $d$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>-process generates a graph at random by starting with an empty graph with <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline3.png\\\" /> <jats:tex-math> $n$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> vertices, then adding edges one at a time uniformly at random among all pairs of vertices which have degrees at most <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline4.png\\\" /> <jats:tex-math> $d-1$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> and are not mutually joined. We show that, in the evolution of a random graph with <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline5.png\\\" /> <jats:tex-math> $n$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> vertices under the <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline6.png\\\" /> <jats:tex-math> $d$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>-process with <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline7.png\\\" /> <jats:tex-math> $d$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> fixed, with high probability, for each <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline8.png\\\" /> <jats:tex-math> $j \\\\in \\\\{0,1,\\\\dots,d-2\\\\}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>, the minimum degree jumps from <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline9.png\\\" /> <jats:tex-math> $j$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> to <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline10.png\\\" /> <jats:tex-math> $j+1$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> when the number of steps left is on the order of <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline11.png\\\" /> <jats:tex-math> $\\\\ln (n)^{d-j-1}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>. This answers a question of Ruciński and Wormald. More specifically, we show that, when the last vertex of degree <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline12.png\\\" /> <jats:tex-math> $j$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> disappears, the number of steps left divided by <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline13.png\\\" /> <jats:tex-math> $\\\\ln (n)^{d-j-1}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> converges in distribution to the exponential random variable of mean <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline14.png\\\" /> <jats:tex-math> $\\\\frac{j!}{2(d-1)!}$ </jats:tex-math> </jats:alternatives> </jats:inline-formula>; furthermore, these <jats:inline-formula> <jats:alternatives> <jats:inline-graphic xmlns:xlink=\\\"http://www.w3.org/1999/xlink\\\" mime-subtype=\\\"png\\\" xlink:href=\\\"S0963548324000105_inline15.png\\\" /> <jats:tex-math> $d-1$ </jats:tex-math> </jats:alternatives> </jats:inline-formula> distributions are independent.\",\"PeriodicalId\":10503,\"journal\":{\"name\":\"Combinatorics, Probability and Computing\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":0.0000,\"publicationDate\":\"2024-04-22\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Combinatorics, Probability and Computing\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://doi.org/10.1017/s0963548324000105\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"\",\"JCRName\":\"\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Combinatorics, Probability and Computing","FirstCategoryId":"1085","ListUrlMain":"https://doi.org/10.1017/s0963548324000105","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
Behaviour of the minimum degree throughout the -process
The $d$ -process generates a graph at random by starting with an empty graph with $n$ vertices, then adding edges one at a time uniformly at random among all pairs of vertices which have degrees at most $d-1$ and are not mutually joined. We show that, in the evolution of a random graph with $n$ vertices under the $d$ -process with $d$ fixed, with high probability, for each $j \in \{0,1,\dots,d-2\}$ , the minimum degree jumps from $j$ to $j+1$ when the number of steps left is on the order of $\ln (n)^{d-j-1}$ . This answers a question of Ruciński and Wormald. More specifically, we show that, when the last vertex of degree $j$ disappears, the number of steps left divided by $\ln (n)^{d-j-1}$ converges in distribution to the exponential random variable of mean $\frac{j!}{2(d-1)!}$ ; furthermore, these $d-1$ distributions are independent.