Volume 57, Issue 1
The Boundedness Below of $2×2$ Upper Triangular Linear Relation Matrices

Ran Huo, Yanyan Du & Junjie Huang

J. Math. Study, 57 (2024), pp. 71-83.

Published online: 2024-03

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  • Abstract
In this note, the boundedness below of linear relation matrix $M_{C}=\left(\begin{smallmatrix}  A & C \\  0 & B\\  \end{smallmatrix} \right)\in LR(H\oplus K)$ is considered, where $A\in CLR(H)$, $B\in CLR(K),$ $C\in BLR(K,H)$, $H,K$ are separable Hilbert spaces. By suitable space decompositions, a necessary and sufficient condition for diagonal relations $A,B$ is given so that $M_{C}$ is bounded below for some $C\in BLR(K,H)$. Besides, the characterization of $\sigma_{ap}(M_{C})$ and $\sigma_{su}(M_{C})$ are obtained, and the relationship between $\sigma_{ap}(M_{0})$ and $\sigma_{ap}(M_{C})$ is further presented.
  • AMS Subject Headings

47A06, 47A10

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COPYRIGHT: © Global Science Press

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@Article{JMS-57-71, author = {Huo , RanDu , Yanyan and Huang , Junjie}, title = {The Boundedness Below of $2×2$ Upper Triangular Linear Relation Matrices}, journal = {Journal of Mathematical Study}, year = {2024}, volume = {57}, number = {1}, pages = {71--83}, abstract = {
In this note, the boundedness below of linear relation matrix $M_{C}=\left(\begin{smallmatrix}  A & C \\  0 & B\\  \end{smallmatrix} \right)\in LR(H\oplus K)$ is considered, where $A\in CLR(H)$, $B\in CLR(K),$ $C\in BLR(K,H)$, $H,K$ are separable Hilbert spaces. By suitable space decompositions, a necessary and sufficient condition for diagonal relations $A,B$ is given so that $M_{C}$ is bounded below for some $C\in BLR(K,H)$. Besides, the characterization of $\sigma_{ap}(M_{C})$ and $\sigma_{su}(M_{C})$ are obtained, and the relationship between $\sigma_{ap}(M_{0})$ and $\sigma_{ap}(M_{C})$ is further presented.
}, issn = {2617-8702}, doi = {https://doi.org/10.4208/jms.v57n1.24.04}, url = {http://global-sci.org/intro/article_detail/jms/22988.html} }
TY - JOUR T1 - The Boundedness Below of $2×2$ Upper Triangular Linear Relation Matrices AU - Huo , Ran AU - Du , Yanyan AU - Huang , Junjie JO - Journal of Mathematical Study VL - 1 SP - 71 EP - 83 PY - 2024 DA - 2024/03 SN - 57 DO - http://doi.org/10.4208/jms.v57n1.24.04 UR - https://global-sci.org/intro/article_detail/jms/22988.html KW - Linear relation matrix, boundedness below, approximate point spectrum, space decomposition. AB -
In this note, the boundedness below of linear relation matrix $M_{C}=\left(\begin{smallmatrix}  A & C \\  0 & B\\  \end{smallmatrix} \right)\in LR(H\oplus K)$ is considered, where $A\in CLR(H)$, $B\in CLR(K),$ $C\in BLR(K,H)$, $H,K$ are separable Hilbert spaces. By suitable space decompositions, a necessary and sufficient condition for diagonal relations $A,B$ is given so that $M_{C}$ is bounded below for some $C\in BLR(K,H)$. Besides, the characterization of $\sigma_{ap}(M_{C})$ and $\sigma_{su}(M_{C})$ are obtained, and the relationship between $\sigma_{ap}(M_{0})$ and $\sigma_{ap}(M_{C})$ is further presented.
Huo , RanDu , Yanyan and Huang , Junjie. (2024). The Boundedness Below of $2×2$ Upper Triangular Linear Relation Matrices. Journal of Mathematical Study. 57 (1). 71-83. doi:10.4208/jms.v57n1.24.04
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