{"title":"扩展近Skolem序列,第三部分","authors":"C. Baker, V. Linek, N. Shalaby","doi":"10.1002/jcd.21851","DOIUrl":null,"url":null,"abstract":"A k $k$ ‐extended q $q$ ‐near Skolem sequence of order n $n$ , denoted by Nnq(k) ${{\\mathscr{N}}}_{n}^{q}(k)$ , is a sequence s1,s2,…,s2n−1 ${s}_{1},{s}_{2},\\ldots ,{s}_{2n-1}$ where sk=0 ${s}_{k}=0$ and for each integer ℓ∈[1,n]\\{q} $\\ell \\in [1,n]\\backslash \\{q\\}$ there are two indices i $i$ , j $j$ such that si=sj=ℓ ${s}_{i}={s}_{j}=\\ell $ and ∣i−j∣=ℓ $| i-j| =\\ell $ . For an Nnq(k) ${{\\mathscr{N}}}_{n}^{q}(k)$ to exist it is necessary that q≡k(mod2) $q\\equiv k\\,(\\mathrm{mod}\\,2)$ when n≡0,1(mod4) $n\\equiv 0,1\\,(\\mathrm{mod}\\,4)$ and q≢k(mod2) $q\\not\\equiv k\\,(\\mathrm{mod}\\,2)$ when n≡2,3(mod4) $n\\equiv 2,3\\,(\\mathrm{mod}\\,4)$ , where (n,q,k)≠(3,2,3) $(n,q,k)\\ne (3,2,3)$ , (4,2,4) $(4,2,4)$ . Any triple (n,q,k) $(n,q,k)$ satisfying these conditions is called admissible. In this manuscript, which is Part III of three manuscripts, we construct the remaining sequences; that is, Nnq(k) ${{\\mathscr{N}}}_{n}^{q}(k)$ for all admissible (n,q,k) $(n,q,k)$ with q∈⌊n+23⌋,⌊n−22⌋ $q\\in \\left[\\lfloor \\frac{n+2}{3}\\rfloor ,\\lfloor \\frac{n-2}{2}\\rfloor \\right]$ and k∈⌊2n3⌋,n−1 $k\\in \\left[\\lfloor \\frac{2n}{3}\\rfloor ,n-1\\right]$ .","PeriodicalId":15389,"journal":{"name":"Journal of Combinatorial Designs","volume":"80 1","pages":"637 - 652"},"PeriodicalIF":0.5000,"publicationDate":"2022-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"2","resultStr":"{\"title\":\"Extended near Skolem sequences, Part III\",\"authors\":\"C. Baker, V. Linek, N. Shalaby\",\"doi\":\"10.1002/jcd.21851\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"A k $k$ ‐extended q $q$ ‐near Skolem sequence of order n $n$ , denoted by Nnq(k) ${{\\\\mathscr{N}}}_{n}^{q}(k)$ , is a sequence s1,s2,…,s2n−1 ${s}_{1},{s}_{2},\\\\ldots ,{s}_{2n-1}$ where sk=0 ${s}_{k}=0$ and for each integer ℓ∈[1,n]\\\\{q} $\\\\ell \\\\in [1,n]\\\\backslash \\\\{q\\\\}$ there are two indices i $i$ , j $j$ such that si=sj=ℓ ${s}_{i}={s}_{j}=\\\\ell $ and ∣i−j∣=ℓ $| i-j| =\\\\ell $ . For an Nnq(k) ${{\\\\mathscr{N}}}_{n}^{q}(k)$ to exist it is necessary that q≡k(mod2) $q\\\\equiv k\\\\,(\\\\mathrm{mod}\\\\,2)$ when n≡0,1(mod4) $n\\\\equiv 0,1\\\\,(\\\\mathrm{mod}\\\\,4)$ and q≢k(mod2) $q\\\\not\\\\equiv k\\\\,(\\\\mathrm{mod}\\\\,2)$ when n≡2,3(mod4) $n\\\\equiv 2,3\\\\,(\\\\mathrm{mod}\\\\,4)$ , where (n,q,k)≠(3,2,3) $(n,q,k)\\\\ne (3,2,3)$ , (4,2,4) $(4,2,4)$ . Any triple (n,q,k) $(n,q,k)$ satisfying these conditions is called admissible. In this manuscript, which is Part III of three manuscripts, we construct the remaining sequences; that is, Nnq(k) ${{\\\\mathscr{N}}}_{n}^{q}(k)$ for all admissible (n,q,k) $(n,q,k)$ with q∈⌊n+23⌋,⌊n−22⌋ $q\\\\in \\\\left[\\\\lfloor \\\\frac{n+2}{3}\\\\rfloor ,\\\\lfloor \\\\frac{n-2}{2}\\\\rfloor \\\\right]$ and k∈⌊2n3⌋,n−1 $k\\\\in \\\\left[\\\\lfloor \\\\frac{2n}{3}\\\\rfloor ,n-1\\\\right]$ .\",\"PeriodicalId\":15389,\"journal\":{\"name\":\"Journal of Combinatorial Designs\",\"volume\":\"80 1\",\"pages\":\"637 - 652\"},\"PeriodicalIF\":0.5000,\"publicationDate\":\"2022-07-25\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Combinatorial Designs\",\"FirstCategoryId\":\"100\",\"ListUrlMain\":\"https://doi.org/10.1002/jcd.21851\",\"RegionNum\":4,\"RegionCategory\":\"数学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q3\",\"JCRName\":\"MATHEMATICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Combinatorial Designs","FirstCategoryId":"100","ListUrlMain":"https://doi.org/10.1002/jcd.21851","RegionNum":4,"RegionCategory":"数学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q3","JCRName":"MATHEMATICS","Score":null,"Total":0}
A k $k$ ‐extended q $q$ ‐near Skolem sequence of order n $n$ , denoted by Nnq(k) ${{\mathscr{N}}}_{n}^{q}(k)$ , is a sequence s1,s2,…,s2n−1 ${s}_{1},{s}_{2},\ldots ,{s}_{2n-1}$ where sk=0 ${s}_{k}=0$ and for each integer ℓ∈[1,n]\{q} $\ell \in [1,n]\backslash \{q\}$ there are two indices i $i$ , j $j$ such that si=sj=ℓ ${s}_{i}={s}_{j}=\ell $ and ∣i−j∣=ℓ $| i-j| =\ell $ . For an Nnq(k) ${{\mathscr{N}}}_{n}^{q}(k)$ to exist it is necessary that q≡k(mod2) $q\equiv k\,(\mathrm{mod}\,2)$ when n≡0,1(mod4) $n\equiv 0,1\,(\mathrm{mod}\,4)$ and q≢k(mod2) $q\not\equiv k\,(\mathrm{mod}\,2)$ when n≡2,3(mod4) $n\equiv 2,3\,(\mathrm{mod}\,4)$ , where (n,q,k)≠(3,2,3) $(n,q,k)\ne (3,2,3)$ , (4,2,4) $(4,2,4)$ . Any triple (n,q,k) $(n,q,k)$ satisfying these conditions is called admissible. In this manuscript, which is Part III of three manuscripts, we construct the remaining sequences; that is, Nnq(k) ${{\mathscr{N}}}_{n}^{q}(k)$ for all admissible (n,q,k) $(n,q,k)$ with q∈⌊n+23⌋,⌊n−22⌋ $q\in \left[\lfloor \frac{n+2}{3}\rfloor ,\lfloor \frac{n-2}{2}\rfloor \right]$ and k∈⌊2n3⌋,n−1 $k\in \left[\lfloor \frac{2n}{3}\rfloor ,n-1\right]$ .
期刊介绍:
The Journal of Combinatorial Designs is an international journal devoted to the timely publication of the most influential papers in the area of combinatorial design theory. All topics in design theory, and in which design theory has important applications, are covered, including:
block designs, t-designs, pairwise balanced designs and group divisible designs
Latin squares, quasigroups, and related algebras
computational methods in design theory
construction methods
applications in computer science, experimental design theory, and coding theory
graph decompositions, factorizations, and design-theoretic techniques in graph theory and extremal combinatorics
finite geometry and its relation with design theory.
algebraic aspects of design theory.
Researchers and scientists can depend on the Journal of Combinatorial Designs for the most recent developments in this rapidly growing field, and to provide a forum for both theoretical research and applications. All papers appearing in the Journal of Combinatorial Designs are carefully peer refereed.