Departments  

Book Series (84) 
1169

Medienwissenschaften 
15

Humanities 
2117

Natural Sciences 
5234

Mathematics  223 
Informatics  305 
Physics  969 
Chemistry  1324 
Geosciences  127 
Human medicine  234 
Stomatology  10 
Veterinary medicine  90 
Pharmacy  144 
Biology  800 
Biochemistry, molecular biology, gene technology  110 
Biophysics  24 
Domestic and nutritional science  44 
Agricultural science  978 
Forest science  201 
Horticultural science  18 
Environmental research, ecology and landscape conservation  141 
Geographie 
1

Engineering 
1638

Common 
84

Leitlinien Unfallchirurgie
5. Auflage bestellen 
Table of Contents, Datei (22 KB)
Extract, Datei (100 KB)
ISBN13 (Printausgabe)  3865374352 
ISBN13 (Hard Copy)  9783865374356 
ISBN13 (eBook)  9783736914353 
Language  Alemán 
Page Number  100 
Edition  1 
Volume  0 
Publication Place  Göttingen 
Place of Dissertation  Berlin 
Publication Date  20050427 
General Categorization  Dissertation 
Departments 
Mathematics

A selfadjoint operator A in a Krein space (K, [•, •]) is called deﬁnitizable if
the resolvent set ρ(A) is nonempty and there exists a polynomial p such that
[p(A)x, x] ≥ 0 for all x ∈ dom (p(A)). It was shown in [L1] and [L5] that a
deﬁnitizable operator A has a spectral function EA which is deﬁned for all real
intervals the boundary points of which do not belong to some ﬁnite subset of the real axis. With the help of the spectral function the real points of the spectrum σ(A) of A can be classiﬁed in points of positive and negative type
and critical points: A point μ ∈ σ(A) ∩ R is said to be of positive type (negative
type) if μ is contained in some open interval δ such that EA is deﬁned and
(EAK, [•, •]) (resp. (EA (δ)K, −[•, •])) is a Hilbert space. Spectral points of
A which are not of deﬁnite type, that is, not of positive or negative type, are
called critical points. The set of critical points of A is ﬁnite; every critical point of A is a zero of any polynomial p with the “deﬁnitizing” property mentioned above. Spectral points of positive and negative type can also be characterized with the help of approximative eigensequences (see [LcMM], [LMM], [J6]), which allows, in a convenient way, to carry over the sign type classiﬁcation of spectral points to nondeﬁnitizable selfadjoint operators and relations in Krein spaces.