id	author	title	date	pages	extension	mime	words	sentence	flesch	summary	cache	txt
iajs-3473	Ali, Dalia S.; Ahmed, Buthainah A.A. 	Perturbation of Weyl’s Theorems for Unbounded  Upper Triangular Operator Matrices	2025	8	.pdf	application/pdf	2769	262	64	The of is defined as ( ) ( ) ( ) An operator ( ) which is Fredholm operator of index is defined as Weyl operator, while ( ) * is not weyl} is used to define the Weyl spectrum of . Since ( ) ( ) ( ) ( ) these conditions imply that and are Fredholm operators, by Lemma (1) and (2), we get is Fredholm operator.	cache/iajs-3473.pdf	txt/iajs-3473.txt