共查询到20条相似文献,搜索用时 78 毫秒
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Let G denote a locally compact Hausdorff group and M(G) be the space of all bounded complex-valued regular Borel measures on G . In this paper, we define two strict topologies on M(G) and study various properties of these topologies such as metrizability, barrelledness and completeness. We also determine the dual space of M(G) and consider various continuity properties for the convolution product on M(G) under these topologies. 相似文献
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In this paper, we introduce the metric dG on a G -metric space (X,G) and use this notion to show that many contraction conditions for maps on the G -metric space (X,G) reduce to certain contraction conditions for maps on the metric space (X,dG). As applications, the proofs of many fixed point theorems for maps on the G -metric space (X,G) may be simplified, and many fixed point theorems for maps on the G -metric space (X,G) are direct consequences of preceding results for maps on the metric space (X,dG). 相似文献
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For a countable ultrahomogeneous graph G=〈G,ρ〉 let P(G) denote the collection of sets A⊂G such that 〈A,ρ∩[A]2〉≅G. The order types of maximal chains in the poset 〈P(G)∪{∅},⊂〉 are characterized as: 相似文献
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Jason Ekstrand Craig Erickson H. Tracy Hall Diana Hay Leslie Hogben Ryan Johnson Nicole Kingsley Steven Osborne Travis Peters Jolie Roat Arianne Ross Darren D. Row Nathan Warnberg Michael Young 《Linear algebra and its applications》2013
The positive semidefinite zero forcing number Z+(G) of a graph G was introduced in Barioli et al. (2010) [4]. We establish a variety of properties of Z+(G): Any vertex of G can be in a minimum positive semidefinite zero forcing set (this is not true for standard zero forcing). The graph parameters tw(G) (tree-width), Z+(G), and Z(G) (standard zero forcing number) all satisfy the Graph Complement Conjecture (see Barioli et al. (2012) [3]). Graphs having extreme values of the positive semidefinite zero forcing number are characterized. The effect of various graph operations on positive semidefinite zero forcing number and connections with other graph parameters are studied. 相似文献
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Let G be a simple connected graph of order n with degree sequence d1,d2,…,dn in non-increasing order. The signless Laplacian spectral radius ρ(Q(G)) of G is the largest eigenvalue of its signless Laplacian matrix Q(G). In this paper, we give a sharp upper bound on the signless Laplacian spectral radius ρ(Q(G)) in terms of di, which improves and generalizes some known results. 相似文献
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A basic geometric question is to determine when a given framework G(p) is globally rigid in Euclidean space Rd, where G is a finite graph and p is a configuration of points corresponding to the vertices of G . G(p) is globally rigid in Rd if for any other configuration q for G such that the edge lengths of G(q) are the same as the corresponding edge lengths of G(p), then p is congruent to q. A framework G(p) is redundantly rigid, if it is rigid and it remains rigid after the removal of any edge of G. 相似文献
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Let F be an infinite field with characteristic not equal to two. For a graph G=(V,E) with V={1,…,n}, let S(G;F) be the set of all symmetric n×n matrices A=[ai,j] over F with ai,j≠0, i≠j if and only if ij∈E. We show that if G is the complement of a partial k -tree and m?k+2, then for all nonsingular symmetric m×m matrices K over F, there exists an m×n matrix U such that UTKU∈S(G;F). As a corollary we obtain that, if k+2?m?n and G is the complement of a partial k-tree, then for any two nonnegative integers p and q with p+q=m, there exists a matrix in S(G;R) with p positive and q negative eigenvalues. 相似文献
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Bárat and the present author conjectured that, for each tree T , there exists a natural number kT such that the following holds: If G is a kT-edge-connected graph such that |E(T)| divides |E(G)|, then G has a T-decomposition, that is, a decomposition of the edge set into trees each of which is isomorphic to T . The conjecture has been verified for infinitely many paths and for each star. In this paper we verify the conjecture for an infinite family of trees that are neither paths nor stars, namely all the bistars S(k,k+1). 相似文献
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Given an arbitrarily weak notion of left-〈f〉-porosity and an arbitrarily strong notion of right-〈g〉-porosity, we construct an example of closed subset of R which is not σ -left-〈f〉-porous and is right-〈g〉-porous. We also briefly summarize the relations between three different definitions of porosity controlled by a function; we then observe that our construction gives the example for any combination of these definitions of left-porosity and right-porosity. 相似文献
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We show that an n-homogeneous polynomial P on the Fourier algebra A(G) of a locally compact group G can be represented in the form P(f)=〈T,fn〉(f∈A(G)) for some T in the group von Neumann algebra VN(G) of G if and only if it is orthogonally additive and completely bounded. 相似文献
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This paper is devoted to a problem of finding the smallest positive integer s(m,n,k) such that (m+1) generic skew-symmetric (k+1)-forms in (n+1) variables as linear combinations of the same s(m,n,k) decomposable skew-symmetric (k+1)-forms. 相似文献
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Let G be a finite group and let d(G) be the minimal number of generators for G . It is well known that d(G)=2 for all (non-abelian) finite simple groups. We prove that d(H)?4 for any maximal subgroup H of a finite simple group, and that this bound is best possible. 相似文献
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Let R(G) be the graph obtained from G by adding a new vertex corresponding to each edge of G and by joining each new vertex to the end vertices of the corresponding edge, and Q(G) be the graph obtained from G by inserting a new vertex into every edge of G and by joining by edges those pairs of these new vertices which lie on adjacent edges of G. In this paper, we determine the Laplacian polynomials of R(G) and Q(G) of a regular graph G; on the other hand, we derive formulae and lower bounds of the Kirchhoff index of these graphs. 相似文献
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A graph G with no isolated vertex is total domination vertex critical if for any vertex v of G that is not adjacent to a vertex of degree one, the total domination number of G-v is less than the total domination number of G . We call these graphs γt-critical. If such a graph G has total domination number k, we call it k -γt-critical. We verify an open problem of k -γt-critical graphs and obtain some results on the characterization of total domination critical graphs of order n=Δ(G)(γt(G)-1)+1. 相似文献
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Let G=(V,E) be a graph. A subset D⊆V is a dominating set if every vertex not in D is adjacent to a vertex in D. A dominating set D is called a total dominating set if every vertex in D is adjacent to a vertex in D. The domination (resp. total domination) number of G is the smallest cardinality of a dominating (resp. total dominating) set of G. The bondage (resp. total bondage) number of a nonempty graph G is the smallest number of edges whose removal from G results in a graph with larger domination (resp. total domination) number of G. The reinforcement (resp. total reinforcement) number of G is the smallest number of edges whose addition to G results in a graph with smaller domination (resp. total domination) number. This paper shows that the decision problems for the bondage, total bondage, reinforcement and total reinforcement numbers are all NP-hard. 相似文献
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Let M=(mij) be a nonnegative irreducible n×n matrix with diagonal entries 0. The largest eigenvalue of M is called the spectral radius of the matrix M , denoted by ρ(M). In this paper, we give two sharp upper bounds of the spectral radius of matrix M. As corollaries, we give two sharp upper bounds of the distance matrix of a graph. 相似文献