【摘要】 本文首先对使得Ak≤0的符号模式矩阵A进行了刻画(k为任意正整数),进而决定了这类矩阵中负元个数的最大值.最后给出了使得A2≤0的符号模式矩阵A的充分必要条件.更多还原

【Abstract】 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.更多还原