Essential sign change numbers of full sign pattern matrices

A sign pattern (matrix) is a matrix whose entries are from the set {+, −, 0} and a sign vector is a vector whose entries are from the set {+, −, 0}. A sign pattern or sign vector is full if it does not contain any zero entries. The minimum rank of a sign pattern matrix A is the minimum of the ranks...

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Main Authors: Chen Xiaofeng, Fang Wei, Gao Wei, Gao Yubin, Jing Guangming, Li Zhongshan, Shao Yanling, Zhang Lihua
Format: Article
Language:English
Published: De Gruyter 2016-06-01
Series:Special Matrices
Subjects:
Online Access:http://www.degruyter.com/view/j/spma.2016.4.issue-1/spma-2016-0023/spma-2016-0023.xml?format=INT
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author Chen Xiaofeng
Fang Wei
Gao Wei
Gao Yubin
Jing Guangming
Li Zhongshan
Shao Yanling
Zhang Lihua
author_facet Chen Xiaofeng
Fang Wei
Gao Wei
Gao Yubin
Jing Guangming
Li Zhongshan
Shao Yanling
Zhang Lihua
author_sort Chen Xiaofeng
collection DOAJ
description A sign pattern (matrix) is a matrix whose entries are from the set {+, −, 0} and a sign vector is a vector whose entries are from the set {+, −, 0}. A sign pattern or sign vector is full if it does not contain any zero entries. The minimum rank of a sign pattern matrix A is the minimum of the ranks of the real matrices whose entries have signs equal to the corresponding entries of A. The notions of essential row sign change number and essential column sign change number are introduced for full sign patterns and condensed sign patterns. By inspecting the sign vectors realized by a list of real polynomials in one variable, a lower bound on the essential row and column sign change numbers is obtained. Using point-line confiurations on the plane, it is shown that even for full sign patterns with minimum rank 3, the essential row and column sign change numbers can differ greatly and can be much bigger than the minimum rank. Some open problems concerning square full sign patterns with large minimum ranks are discussed.
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spelling doaj.art-1cece89564a7494389759f66989e9af22022-12-21T21:35:49ZengDe GruyterSpecial Matrices2300-74512016-06-014110.1515/spma-2016-0023spma-2016-0023Essential sign change numbers of full sign pattern matricesChen Xiaofeng0Fang Wei1Gao Wei2Gao Yubin3Jing Guangming4Li Zhongshan5Shao Yanling6Zhang Lihua7College of Math and Stat, Chongqing Jiaotong University, Chongqing, ChinaSchool of Instrument & Electronics, North University of China, Shanxi, ChinaDept of Math and Stat, Georgia State University, Atlanta, GA 30302, USADept of Math, North University of China, Taiyuan, Shanxi, ChinaDept of Math and Stat, Georgia State University, Atlanta, GA 30302, USADept of Math and Stat, Georgia State University, Atlanta, GA 30302, USADept of Math, North University of China, Taiyuan, Shanxi, ChinaDept of Math and Stat, Georgia State University, Atlanta, GA 30302, USAA sign pattern (matrix) is a matrix whose entries are from the set {+, −, 0} and a sign vector is a vector whose entries are from the set {+, −, 0}. A sign pattern or sign vector is full if it does not contain any zero entries. The minimum rank of a sign pattern matrix A is the minimum of the ranks of the real matrices whose entries have signs equal to the corresponding entries of A. The notions of essential row sign change number and essential column sign change number are introduced for full sign patterns and condensed sign patterns. By inspecting the sign vectors realized by a list of real polynomials in one variable, a lower bound on the essential row and column sign change numbers is obtained. Using point-line confiurations on the plane, it is shown that even for full sign patterns with minimum rank 3, the essential row and column sign change numbers can differ greatly and can be much bigger than the minimum rank. Some open problems concerning square full sign patterns with large minimum ranks are discussed.http://www.degruyter.com/view/j/spma.2016.4.issue-1/spma-2016-0023/spma-2016-0023.xml?format=INTsign pattern (matrix) full sign pattern minimum rank sign change number essential row sign change number essential column sign change number sign vectors of a list of polynomials
spellingShingle Chen Xiaofeng
Fang Wei
Gao Wei
Gao Yubin
Jing Guangming
Li Zhongshan
Shao Yanling
Zhang Lihua
Essential sign change numbers of full sign pattern matrices
Special Matrices
sign pattern (matrix)
full sign pattern
minimum rank
sign change number
essential row sign change number
essential column sign change number
sign vectors of a list of polynomials
title Essential sign change numbers of full sign pattern matrices
title_full Essential sign change numbers of full sign pattern matrices
title_fullStr Essential sign change numbers of full sign pattern matrices
title_full_unstemmed Essential sign change numbers of full sign pattern matrices
title_short Essential sign change numbers of full sign pattern matrices
title_sort essential sign change numbers of full sign pattern matrices
topic sign pattern (matrix)
full sign pattern
minimum rank
sign change number
essential row sign change number
essential column sign change number
sign vectors of a list of polynomials
url http://www.degruyter.com/view/j/spma.2016.4.issue-1/spma-2016-0023/spma-2016-0023.xml?format=INT
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AT gaoyubin essentialsignchangenumbersoffullsignpatternmatrices
AT jingguangming essentialsignchangenumbersoffullsignpatternmatrices
AT lizhongshan essentialsignchangenumbersoffullsignpatternmatrices
AT shaoyanling essentialsignchangenumbersoffullsignpatternmatrices
AT zhanglihua essentialsignchangenumbersoffullsignpatternmatrices