Weighted operator least squares problems and the J‐trace in Krein spaces. Issue 9 (29th June 2020)

• Record Type: Journal Article
• Authors: Contino, Maximiliano; Maestripieri, Alejandra; Marcantognini, Stefania
• Is Part Of: Mathematische Nachrichten. Volume 293:Issue 9(2020)
• Page Start: 1730
• Page End: 1745
• Publication Date: 2020-06-29
• Subjects: Krein spaces -- oblique projections -- weighted operator approximation; Mathematics -- Periodicals; 510.5
• DOI: 10.1002/mana.201900066
• Languages: English
• ISSNs: 0025-584X

Abstract

Abstract: Given B, C and W operators in the algebra L ( H ) of bounded linear operators on the Krein space H, the minimization problem min ( B X − C ) # W ( B X − C ), for X ∈ L ( H ), is studied when the weight W is selfadjoint. The analogous maximization and min‐max problems are also considered. Complete answers to these problems and to those naturally associated to trace clase operators on Krein spaces are given.