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Bibliographic Details
Main Authors: Fischbacher, Christoph, Gesztesy, Fritz, Littlejohn, Lance L.
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2504.06506
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author Fischbacher, Christoph
Gesztesy, Fritz
Littlejohn, Lance L.
author_facet Fischbacher, Christoph
Gesztesy, Fritz
Littlejohn, Lance L.
contents This largely pedagogical paper recalls some facts on defect numbers of products of closed operators employing results from the theory of semi-Fredholm operators and then applies these facts to positive integer powers of symmetric operators and subsequently to certain minimal Sturm--Liouville and minimal higher even-order ordinary and partial differential operators. We also point out some unexpected missed opportunities when comparing the work of different groups on this subject.
format Preprint
id arxiv_https___arxiv_org_abs_2504_06506
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Some Remarks on the Product Formula for Defect Numbers of Closed Operators
Fischbacher, Christoph
Gesztesy, Fritz
Littlejohn, Lance L.
Functional Analysis
Mathematical Physics
Primary: 47A05, 47A53. Secondary: 47B02, 47E05, 47F05
This largely pedagogical paper recalls some facts on defect numbers of products of closed operators employing results from the theory of semi-Fredholm operators and then applies these facts to positive integer powers of symmetric operators and subsequently to certain minimal Sturm--Liouville and minimal higher even-order ordinary and partial differential operators. We also point out some unexpected missed opportunities when comparing the work of different groups on this subject.
title Some Remarks on the Product Formula for Defect Numbers of Closed Operators
topic Functional Analysis
Mathematical Physics
Primary: 47A05, 47A53. Secondary: 47B02, 47E05, 47F05
url https://arxiv.org/abs/2504.06506