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International Journal of Mathematics and Mathematical Sciences
Volume 2018, Article ID 5178454, 7 pages
Research Article

An Extension Theorem for a Sequence of Krein Space Contractions

Department of Mathematics and Statistics, Sultan Qaboos University, P.O. Box 36, Al-Khod, 123 Muscat, Oman

Correspondence should be addressed to Gerald Wanjala; moc.oohay@galajnaw

Received 8 December 2017; Revised 23 January 2018; Accepted 30 January 2018; Published 1 March 2018

Academic Editor: Gelu Popescu

Copyright © 2018 Gerald Wanjala. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Consider Krein spaces and and let and be regular subspaces of and , respectively, such that and . For each , let be a contraction. We derive necessary and sufficient conditions for the existence of a contraction such that . Some interesting results are proved along the way.