共查询到17条相似文献,搜索用时 31 毫秒
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对称本原矩阵指数集的刻画 总被引:1,自引:0,他引:1
设Sn表示由全体n阶对称本原(0,1)-矩所构成的集合,并设S(n,d)={A∈Sn│A的伴随有向图中的最小奇圈之长为d≥1}。本文证明了:S(n,d)的本原指数集为{d-1,d,…,2n-d-1}\D,其中D为{n-d+1,n-d+2,…,2n-d-2}中的所有奇数与0之并集,同时,我们也给出了S(n,d)中指数达到上界的矩阵集合的完全刻画。 相似文献
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设 E_n 为 n 阶本原矩阵类的指数集,[1,λ_n]为 E_n 中的一个最大连续指数集.本文证明了存在某一类矩阵,它具有最大连续指数集[1,λ_n],从而完全解决了文献[1]中提出的两个问题. 相似文献
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设E_n为n阶本原矩阵类的指数集,[1,λ_n]为E_n中的一个最大连续指数集。本文证明了存在某一类矩阵(?),它具有最大连续指数集[1,λ_n],从而完全解决了文献[1]中提出的两个问题。 相似文献
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引入了本原无限布尔方阵的概念,给出了无限布尔方阵为本原阵的一个充分必要条件,最后给出了一类本原无限布尔方阵的本原指数集的刻划. 相似文献
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对称本原有向图的广义本原指数集 总被引:3,自引:0,他引:3
本文证明了全体n阶对称本原有向图的第k个第一类(1≤k<n-1)、第二类(1≤k≤n-1)和第三类(2≤k≤n-1)广义本原指数的指数集分别是{1,2,…,n-2+k}和{1,2,…,2(n-k)},其中「a]表不小于a的最小整数,[b]表不大于b的最大整数。 相似文献
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广义本原指数及其极图的完全刻划 总被引:2,自引:0,他引:2
本文利用图论和数论相结合的方法,给出了广义本原指数达到最大值和次大值的极图的完全刻划,解决了文[3]中提到的EM问题,并同时证明了广义本原指数集合中缺数段的存在性。本文还给出了对称本原有向图类中广义本原指数达到最大值的极图的完全刻划。 相似文献
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研究了围长为2的无限布尔方阵的本原性,通过无限有向图D(A)的直径给出了这类矩阵的本原指数的上确界,最后证明了直径小于等于d且围长为2的本原无限布尔方阵所构成的矩阵类的本原指数集为Ed^0={2,3,…,3d}. 相似文献
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We obtain upper bounds on the Hall exponents of symmetric and microsymmetric primitive Boolean matrices respectively. 相似文献
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We obtain upper bounds on the Hall exponents of symmetric and microsymmetric primitive Boolean matrices respectively. 相似文献
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Let D =(V,E)be a primitive digraph.The vertex exponent of D at a vertex v∈V,denoted by exPD(V),is the least integer p such that there is a v→u walk of length p for each u∈V.Following Brualdi and Liu,we order the vertices of D so that exPD(v_1)≤exPD(v_2)≤…≤exPD(v_n).Then exPD(v_k)is called the k- point exponent of D and is denoted by exP_D(k),1≤k≤n.In this paper we define e(n,k):=max{exp_D(k)|D∈PD(n,2)} and E(n,k):= {expD(k)|D∈PD(n,2)},where PD(n,2)is the set of all primitive digraphs of order n with girth 2.We completely determine e(n,k)and E(n,k)for all n,k with n≥3 and 1≤k≤n. 相似文献
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51.IntroductionandNotationsLetD=(V,E)beadigraphandL(D)denotethesetofcyclelengthsofD.ForuEVandintegeri21,letfo(u):={vEVIthereedestsadirectedwalkoflengthifromutov}.WedelveRo(u):={u}.Letu,vEV.IfN (v)=N (v)andN--(v)=N--(v),thenwecanvacopyofu.LotDbeaprimitivedigraphand7(D)denotetheexponentofD.In1950,H.WielandtI61foundthat7(D)5(n--1)' 1andshowedthatthereisapiquedigraphthatattainsthisbound.In1964,A.L.DulmageandN.S.Mendelsohn[2]ObservedthattherearegapsintheexponentsetEd={ry(D)IDEPD.}… 相似文献
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The scrambling index of an n×n primitive matrix A is the smallest positive integer k such that Ak(At)k=J, where At denotes the transpose of A and J denotes the n×n all ones matrix. For an m×n Boolean matrix M, its Boolean rank b(M) is the smallest positive integer b such that M=AB for some m×b Boolean matrix A and b×n Boolean matrix B. In this paper, we give an upper bound on the scrambling index of an n×n primitive matrix M in terms of its Boolean rank b(M). Furthermore we characterize all primitive matrices that achieve the upper bound. 相似文献
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Let D = (V, E) be a primitive digraph. The vertex exponent of D at a vertex v∈ V, denoted by expD(v), is the least integer p such that there is a v →u walk of length p for each u ∈ V. Following Brualdi and Liu, we order the vertices of D so that exPD(V1) ≤ exPD(V2) …≤ exPD(Vn). Then exPD(Vk) is called the k- point exponent of D and is denoted by exPD (k), 1≤ k ≤ n. In this paper we define e(n, k) := max{expD (k) | D ∈ PD(n, 2)} and E(n, k) := {exPD(k)| D ∈ PD(n, 2)}, where PD(n, 2) is the set of all primitive digraphs of order n with girth 2. We completely determine e(n, k) and E(n, k) for all n, k with n ≥ 3 and 1 ≤ k ≤ n. 相似文献