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On the deficiency index of even order symmetric differential expressions with essential spectrum
Author(s) -
Roque Marian P.,
Schultze Bernd
Publication year - 2011
Publication title -
mathematische nachrichten
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.913
H-Index - 50
eISSN - 1522-2616
pISSN - 0025-584X
DOI - 10.1002/mana.200810141
Subject(s) - mathematics , spectrum (functional analysis) , order (exchange) , essential spectrum , combinatorics , differential (mechanical device) , mathematical physics , pure mathematics , physics , quantum mechanics , thermodynamics , finance , economics
It shall be shown that for every n , \documentclass{article}\usepackage{amssymb}\pagestyle{empty}\begin{document}$k \in \mathbb {N}$\end{document} with n ⩽ k < 2 n , there exist real symmetric differential expressions M of order 2 n with nonempty essential spectrum such that d ( M ) = k . © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim