On a Beurling-Arveson Type Theorem for Some Functional Hilbert Spaces and Related Questions

2008 ◽  
Vol 62 (1) ◽  
pp. 77-84 ◽  
Author(s):  
M. T. Karaev
1985 ◽  
Vol 31 (1) ◽  
pp. 117-126 ◽  
Author(s):  
R.K. Singh ◽  
R. David Chandra Kumar

Let X be a non-empty set and let H(X) denote a Hibert space of complex-valued functions on X. Let T be a mapping from X to X and θ a mapping from X to C such that for all f in H(X), f ° T is in H(x) and the mappings CT taking f to f ° T and M taking f to θ.f are bounded linear operators on H(X). Then the operator CTMθ is called a weighted composition operator on H(X). This note is a report on the characterization of weighted composition operators on functional Hilbert spaces and the computation of the adjoint of such operators on L2 of an atomic measure space. Also the Fredholm criteria are discussed for such classes of operators.


1983 ◽  
Vol 27 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Peter Greim

Let (ωi, σi, μi.) be two positive finite measure spaces, V a non-zero Hilbert space, and 1 ≤ p < ∞, p # 2. In this article it is shown that each surjective linear isometry between the Bochner spaces induces a Boolean isomorphism between the measure algebras , thus generalizing a result of Cambern's for separable Hilbert spaces.This Banach–Stone type theorem is achieved via a description of the Lp-structure of .


1995 ◽  
Vol 51 (2) ◽  
pp. 235-248 ◽  
Author(s):  
Robert Deville ◽  
El Mahjoub El Haddad

We prove a formula for the second order subdifferential of the sum of two lower semi continuous functions in finite dimensions. This formula yields an Alexandrov type theorem for continuous functions. We derive from this uniqueness results of viscosity solutions of second order Hamilton-Jacobi equations and singlevaluedness of the associated Hamilton-Jacobi operators. We also provide conterexamples in infinite dimensional Hilbert spaces.


1980 ◽  
Vol 21 (1) ◽  
pp. 125-130 ◽  
Author(s):  
R.K. Singh ◽  
S.D. Sharma

In this note sufficient conditions for non-compactness of composition operators on two different functional Hilbert spaces have been obtained.


Sign in / Sign up

Export Citation Format

Share Document