本論文主要了解Perturbation Theory,對於在有限 維複數向量空間上的eigenvalue problem,當線性算子T受到微小 擾動時,eigenvalue和eigenvector如何改變。第一章主要解釋重要 的定理,第二章主要是數學上基本定理及常用公式知識,第三 章主要是證明第一章,及公式推導 這篇論文是一個關於Kato的 Perturbation Theory of Linear Operators書的讀書心得報告關於 KATO所著的Perturbation Theory of Linear Operators書, 且藉由 一些例子去理解裡面的定理及內容. We now go into the perturbation theory for the eigenvalue prob- lem in a nite-dimensional vector space X over C. A typical prob- lem of this theory is to investigate how the eigenvalues and eigen- vectors (or eigenspaces) of a linear operator T change when T is subjected to a small perturbation. We give introduction in the rst chapter , methametical basic theory and the knowledge in the sec- ond chapter and proofs in the third chapter. This article is mainly about Kato's book "Perturbation Theory of Linear Operators" and how to understand the theory and the content of the book through examples.