TY  - JOUR
AU  - Tarcsay, Zsigmond
TI  - On the parallel sum of positive operators, forms, and functionals
JF  - ACTA MATHEMATICA HUNGARICA
J2  - ACTA MATH HUNG
VL  - 147
PY  - 2015
IS  - 2
SP  - 408
EP  - 426
PG  - 19
SN  - 0236-5294
DO  - 10.1007/s10474-015-0533-6
UR  - https://m2.mtmt.hu/api/publication/2937121
ID  - 2937121
N1  - Cited By :7            
            Export Date: 9 June 2022            
            Correspondence Address: Tarcsay, Z.; Department of Applied Analysis, Eötvös L. University, Pázmány Péter sétány 1/c., Hungary
AB  - The parallel sum (Formula presented.) of two bounded positive linear operators A, B on a Hilbert space H is defined to be the positive operator having the quadratic form(Formula presented.)for fixed (Formula presented.). The purpose of this paper is to provide a factorization of the parallel sum of the form (Formula presented.) where (Formula presented.) is the embedding operator of an auxiliary Hilbert space associated with A and B, and P is an orthogonal projection onto a certain linear subspace of that Hilbert space. We give similar factorizations of the parallel sum of nonnegative Hermitian forms, positive operators of a complex Banach space E into its topological anti-dual (Formula presented.), and of representable positive functionals on a (Formula presented.)-algebra. © 2015 Akadémiai Kiadó, Budapest, Hungary
LA  - English
DB  - MTMT
ER  - 

TY  - JOUR
AU  - Titkos, Tamás
TI  - On Means of Nonnegative Sesquilinear Forms
JF  - ACTA MATHEMATICA HUNGARICA
J2  - ACTA MATH HUNG
VL  - 143
PY  - 2014
SP  - 515
EP  - 533
PG  - 19
SN  - 0236-5294
DO  - 10.1007/s10474-014-0416-2
UR  - https://m2.mtmt.hu/api/publication/2569368
ID  - 2569368
N1  - Export Date: 2 January 2019            
            Correspondence Address: Titkos, T.; Department of Applied Analysis, Eötvös Loránd University, Pázmány Péter sétany 1/c, H-1117 Budapest, Hungary; email: titkos@cs.elte.hu
Cited By :1            
            Export Date: 5 September 2019            
            Correspondence Address: Titkos, T.; Department of Applied Analysis, Eötvös Loránd University, Pázmány Péter sétany 1/c, H-1117 Budapest, Hungary; email: titkos@cs.elte.hu
AB  - The aim of this paper is to generalize the theory of operator connections for nonnegative sesquilinear forms. As an application, we investigate the case of bounded finitely additive set functions. One of the most important connections in this setting is the parallel sum. We introduce this notion, and in addition, we present a Lebesgue-type decomposition theorem for such functions. © 2014 Akadémiai Kiadó, Budapest, Hungary.
LA  - English
DB  - MTMT
ER  -