Basic Tools of Functional Analysis
Bilel Krichen · 2025
This chapter provides an introduction to the foundational concepts, notations, and elementary results necessary for the study of spectral theory. A solid understanding of bounded and unbounded Fredholm operators is essential for this subject, and this chapter aims to equip readers with the required background. The material presented here aligns with standard results found in most classical texts on functional analysis (e.g., [ 8 , 17 , 10 ]).