Minimum rank problems
نویسندگان
چکیده
منابع مشابه
Minimum Rank Problems
A graph describes the zero-nonzero pattern of a family of matrices, with the type of graph (undirected or directed, simple or allowing loops) determining what type of matrices (symmetric or not necessarily symmetric, diagonal entries free or constrained) are described by the graph. The minimum rank problem of the graph is to determine the minimum among the ranks of the matrices in this family; ...
متن کاملZero forcing parameters and minimum rank problems
Abstract. The zero forcing number Z(G), which is the minimum number of vertices in a zero forcing set of a 1 graph G, is used to study the maximum nullity/minimum rank of the family of symmetric matrices described by 2 G. It is shown that for a connected graph of order at least two, no vertex is in every zero forcing set. The positive 3 semidefinite zero forcing number Z+(G) is introduced, and ...
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Abstract Our main result is a sharp bound for the number of vertices in a minimal forbidden subgraph for the graphs having minimum rank at most 3 over the finite field of order 2. We also list all 62 such minimal forbidden subgraphs. We conclude by exploring how some of these results over the finite field of order 2 extend to arbitrary fields and demonstrate that at least one third of the 62 ar...
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Abstract. Let G be an undirected graph on n vertices and let S(G) be the set of all real symmetric n×n matrices whose nonzero off-diagonal entries occur in exactly the positions corresponding to the edges of G. Let mr(G) denote the minimum rank of all matrices in S(G), and mr+(G) the minimum rank of all positive semidefinite matrices in S(G). All graphs G with mr(G) = 2 and mr+(G) = k are chara...
متن کاملMinimum Rank of Graphs with Loops
A loop graph G is a finite undirected graph that allows loops but does not allow multiple edges. The set S(G) of real symmetric matrices associated with a loop graph G of order n is the set of symmetric matrices A = [aij ] ∈ R such that aij 6= 0 if and only if ij ∈ E(G). The minimum (maximum) rank of a loop graph is the minimum (maximum) of the ranks of the matrices in S(G). Loop graphs having ...
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ژورنال
عنوان ژورنال: Linear Algebra and its Applications
سال: 2010
ISSN: 0024-3795
DOI: 10.1016/j.laa.2009.05.003