论文标题
巴雷特·约翰逊(Barrett-Johnson)完全非负矩阵的不平等现象
Barrett-Johnson inequalities for totally nonnegative matrices
论文作者
论文摘要
给定一个矩阵$ a $,令$ a_ {i,j} $表示$ a $的combatrix由$ i $和列$ j $确定。 Fischer的不平等表明,对于每个$ n \ times n $ hermitian阳性半矩阵$ a $ a $,每个子集$ i $的$ \ {1,\ dotsc,n \} $及其补充$ i^c $ \ det(a_ {i,i})\ det(a_ {i^c,i^c})$。 Barrett和Johnson(线性多线性代数34,1993)将其扩展到规定不平等的主要未成年人产物的总和,其订单的订单是通过非插入整数序列$(λ_1,\ dotsc,λ_r)$,$(μ_1,$ __1,\ dotsc,\ dotsc,\ dotsc,\ dotsc,μ__s)$ n $ n。具体来说,如果$λ_1+\ cdots+λ_i\leqμ_1+\ cdots+μ_i$用于所有$ i $,则是$λ_1!\cdotsλ_r! \ sum _ {(i_1,\ dotsc,i_r)} \ det(a_ {a_ {i_1,i_1})\ cdots \ det(a__ {i_r,i_r,i_r})〜\ geq〜 μ_1!\cdotsμ_s! \ sum _ {(J_1,\ dotsc,j_s)} \ det(a_ {j_1,j_1})\ cdots \ det(a_ {a_ {j_s,j_s}),$$,$ \ {1,\ dotsc,n \ dotsc,n \} $满意=λ_k$,$ | j_k | =μ_k$。我们表明,这些不平等也适用于完全非负矩阵。
Given a matrix $A$, let $A_{I,J}$ denote the submatrix of $A$ determined by rows $I$ and columns $J$. Fischer's Inequalities state that for each $n \times n$ Hermitian positive semidefinite matrix $A$, and each subset $I$ of $\{1,\dotsc,n\}$ and its complement $I^c$, we have $\det(A) \leq \det(A_{I,I})\det(A_{I^c,I^c})$. Barrett and Johnson (Linear Multilinear Algebra 34, 1993) extended these to state inequalities for sums of products of principal minors whose orders are given by nonincreasing integer sequences $(λ_1,\dotsc,λ_r)$, $(μ_1,\dotsc,μ_s)$ summing to $n$. Specifically, if $λ_1+\cdots+λ_i\leq μ_1+\cdots+μ_i$ for all $i$, then $$ λ_1!\cdotsλ_r! \sum_{(I_1,\dotsc,I_r)} \det(A_{I_1,I_1}) \cdots \det(A_{I_r,I_r}) ~\geq~ μ_1!\cdotsμ_s! \sum_{(J_1,\dotsc,J_s)} \det(A_{J_1,J_1}) \cdots \det(A_{J_s,J_s}), $$ where sums are over sequences of disjoint subsets of $\{1,\dotsc,n\}$ satisfying $|I_k| = λ_k$, $|J_k| = μ_k$. We show that these inequalities hold for totally nonnegative matrices as well.