论文标题

多项式的操作员根:ISO对称操作员

Operator roots of polynomials:iso-symmetric operators

论文作者

Duggal, B. P., Kim, I. H.

论文摘要

Given Hilbert space operators $A_i, B_i$, $i=1,2$, and $X$ such that $A_1​​$ commutes with $A_2$ and $B_!$ commutes with $B_2$, and integers $m, n\geq 1$, we say that the pairs of operators $(B_1,A_1)$ and $(B_2,A_2)$ are left-$(X, (m,n))$ - 对称,表示$((b_1,a_1),(b_2,a_2))\ in {\ rm左} (-1)^{j+k} \ left(\ begin {arnay} {clcr} m \\ j \ end {array} a_2^{n-k} a_1^{j} = 0。$$左 - $(x,(m,n))的重要类 - $ symmetric运算符在选择$ b_1 = b_1 = b_1 = a^*_ 1 = a^*_ 1 = a^*_^*_^*_ 2 = a^*= a^*$^$和$ x = i $的$($ x = i $)的$($ iSOS and $ nptiration and)and san) $(m,n)的最大不变子空间 - $ sosymmetric运算符已由Stankus \ cite {st}执行。当前的工作认为在扰动下通过通勤NILPOTENTS和通勤产品左-(x,(m,n)) - $对称操作员来考虑稳定性。可以看出,$(x,(m,n)) - $ sosymmmetric drazin可逆操作员$ a $具有特别有趣的结构。

Given Hilbert space operators $A_i, B_i$, $i=1,2$, and $X$ such that $A_1$ commutes with $A_2$ and $B_!$ commutes with $B_2$, and integers $m, n\geq 1$, we say that the pairs of operators $(B_1,A_1)$ and $(B_2,A_2)$ are left-$(X, (m,n))$-symmetric, denoted $((B_1,A_1),(B_2,A_2))\in {\rm left}-(X,(m,n))-{\rm symmetric}$ if $$ \sum_{j=0}^m\sum_{k=0}^n (-1)^{j+k}\left(\begin{array}{clcr}m\\j\end{array}\right) \left(\begin{array}{clcr}n\\k\end{array}\right) B_1^{m-j}B_2^{n-k} X A_2^{n-k}A_1^{j}=0.$$An important class of left-$(X,(m,n))-$symmetric operators is obtained uponchoosing $B_1=B_2=A^*_1=A^*_2=A^*$ and $X=I$: such operators have been called $(m,n)-$isosymmetric, and a study of the spectral picture and maximal invariant subspaces of $(m,n)-$isosymmetric operators has been carried out by Stankus \cite{St}. The current work considers stability under perturbations by commuting nilpotents, and products of commuting, left-$(X, (m,n))-$symmetric operators. It is seen that $(X, (m,n))-$isosymmetric Drazin invertible operators $A$ have a particularly interesting structure.

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