WANG Yan-bo 1 , JIANG Guang-feng 2 (1.Institute of Communications Engineering,PLA University of Science and Technology,Nanjing 210016,China; 2.Department of Mathematics and Information Science,Beijing University of Ch...WANG Yan-bo 1 , JIANG Guang-feng 2 (1.Institute of Communications Engineering,PLA University of Science and Technology,Nanjing 210016,China; 2.Department of Mathematics and Information Science,Beijing University of Chemical Technology,Beijing 100029,P.R.China)展开更多
A matrix whose entries are +,-, and 0 is called a sign pattern matrix. Let k be arbitrary positive integer. We first characterize sign patterns A such that .Ak≤0. Further, we determine the maximum number of negative ...A matrix whose entries are +,-, and 0 is called a sign pattern matrix. Let k be arbitrary positive integer. We first characterize sign patterns A such that .Ak≤0. Further, we determine the maximum number of negative entries that can occur in A whenever Ak≤0. Finally, we give a necessity and sufficiency condition for A2≤0.展开更多
基金The research of the second author was supported by BUCTNSFC( 199871974) The second named author is the correspondent
文摘WANG Yan-bo 1 , JIANG Guang-feng 2 (1.Institute of Communications Engineering,PLA University of Science and Technology,Nanjing 210016,China; 2.Department of Mathematics and Information Science,Beijing University of Chemical Technology,Beijing 100029,P.R.China)
基金Supported by Shanxi Natural Science Foundation(20011006)
文摘A matrix whose entries are +,-, and 0 is called a sign pattern matrix. Let k be arbitrary positive integer. We first characterize sign patterns A such that .Ak≤0. Further, we determine the maximum number of negative entries that can occur in A whenever Ak≤0. Finally, we give a necessity and sufficiency condition for A2≤0.
