OSUVA - Selaus tekijän "Wietsma, Hendrik Luit" mukaan
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Generalized Schur Functions as Multivalent Functions
Wietsma, Hendrik Luit (Springer, 14.01.2021)
articleThe multivalency approach to generalized Nevanlinna functions established in Wietsma (Indag Math 29:997–1008, 2018) is here extended to the related class of generalized Schur functions giving thereby rise to new characterizations ... -
On unitary relations between Kreĭn spaces
Wietsma, Hendrik Luit (Vaasan yliopisto, 2012)
Monografiaväitöskirja -
Spectral Decompositions of Selfadjoint Relations in Pontryagin Spaces and Factorizations of Generalized Nevanlinna Functions
Hassi, Seppo; Wietsma, Hendrik Luit; Alpay, Daniel; Fritzsche, Bernd; Kirstein, Bernd (Birkhäuser, 19.09.2020)
bookPartSelfadjoint relations in Pontryagin spaces do not possess a spectral family completely characterizing them in the way that selfadjoint relations in Hilbert spaces do. Here it is shown that a combination of a factorization ... -
The factorization of generalized Nevanlinna functions and the invariant subspace property
Wietsma, Hendrik Luit (Elsevier, 01.01.2019)
articleThe well-known invariant subspace property of selfadjoint relations (multi-valued operators) in Pontryagin spaces is shown to be equivalent to the factorization property of (scalar) generalized Nevanlinna functions. This ...