Results 11 to 20 of about 2,695 (277)
Bounded Functional Calculi for Unbounded Operators [PDF]
Operator Theory: Advances and Applications, 2023 This article summarises the theory of several bounded functional calculi for unbounded operators that have recently been discovered. The extend the Hille--Phillips calculus for (negative) generators $A$ of certain bounded $C_0$-semigroups, in particular for bounded semigroups on Hilbert spaces and bounded holomorphic semigroups on Banach spaces.
Yuri Tomilov +2 more
exaly +5 more sources
BOUNDED AND UNBOUNDED OPERATORS SIMILAR TO THEIR ADJOINTS
Bulletin of the Korean Mathematical Society, 2017 08 ...
Mohammed Hichem Mortad, Souheyb Dehimi
exaly +4 more sources
On nth roots of bounded and unbounded quasinormal operators [PDF]
Annali di Matematica Pura ed Applicata (1923 -), 2022 AbstractIn a recent paper (JFA 278:108342, 2020), R. E. Curto, S. H. Lee and J. Yoon asked the following question: LetTbe a subnormal operator, and assume that$$T^2$$ T 2 is quasinormal. Does it follow thatTis quasinormal? In (JFA 280:109001, 2021) we answered
Pietrzycki, Paweł, Stochel, Jan
openaire +4 more sources
Commutativity up to a factor for bounded and unbounded operators
Journal of Mathematical Analysis and Applications, 2014 In this paper, we further investigate the problem of commutativity up to a factor (or $λ$-commutativity) in the setting of bounded and unbounded linear operators in a complex Hilbert space. The results are based on a new approach to the problem. We finish the paper by a conjecture on the commutativity of self-adjoint operators.
Mohammed Hichem Mortad
exaly +3 more sources
Extension of Spectral Scales to Unbounded Operators [PDF]
International Journal of Mathematics and Mathematical Sciences, 2010 We extend the notion of a spectral scale to n-tuples of unbounded operators affiliated with a finite von Neumann Algebra. We focus primarily on the single-variable case and show that many of the results from the bounded theory go through in the unbounded
M. D. Wills
doaj +2 more sources
Unbounded or bounded idempotent operators in Hilbert space
Linear Algebra and Its Applications, 2013 A densely defined closed linear operator \(F\) in a Hilbert space is said to be idempotent if \(\text{ran}(F)\subset \text{dom}(F)\) and \(F\cdot F = F\). The author shows that such an idempotent operator can be written as \(F = P(P + Q )^{-1/2} \cdot (P + Q )^{-1/2}\), where \(P\) and \(Q\) are the orthoprojections onto \(\text{ran}(F)\) and \(\ker(F)\
Tsuyoshi Ando
exaly +3 more sources
On Stokes operators with variable viscosity in bounded and unbounded domains [PDF]
Mathematische Annalen, 2008 The authors consider the Stokes problem with non-constant viscosity \(\nu(x)\) in bounded or unbounded domains in \(\mathbb R^d\). They assume \(\nu(x) = \nu_\infty + \nu'(x)\), \(\nu' \in W^{1,r_1}(\Omega)\) and \(\partial \Omega \in W^{2-1/r_2,r_2}\) with ...
Helmut Abels
exaly +2 more sources
Schrödinger operators with δ and δ′-potentials supported on hypersurfaces [PDF]
, 2013 Self-adjoint Schrödinger operators with δ and δ′-potentials supported on a smooth compact hypersurface are defined explicitly via boundary conditions.
Lotoreichik, Vladimir +2 more
core +4 more sources
Extensional and Intensional Semantics of Bounded and Unbounded Nondeterminism [PDF]
Logical Methods in Computer Science, 2021 We give extensional and intensional characterizations of functional programs with nondeterminism: as structure preserving functions between biorders, and as nondeterministic sequential algorithms on ordered concrete data structures which compute them.
James Laird
doaj +1 more source
A maximal theorem for holomorphic semigroups. [PDF]
, 2005 Let X be a closed linear subspace of the Lebesgue space L^p(Omega ; mu); let -A be an invertible linear operator that is the generator of abounded holomorphic semigroup T_t on X.
Doust, Ian, Blower, Gordon
core +4 more sources