5,799 research outputs found
A Theorem of Rolewicz's Type for Measurable Evolution Families in Banach Spaces
No full textLet be a positive and non-decreasing function defined on the real half-line and be a strongly measurable, exponentially bounded evolution family of bounded linear operators acting on a Banach space and satisfing a certain measurability condition as in Theorem 1 below. We prove that if and satisfy a certain integral condition (see the relation ef{0.1} from Theorem 1 below) then is uniformly exponentially stable. For continuous and strongly continuous and exponentially bounded, this result is due to Rolewicz. The proofs uses the relatively recent techniques involving evolution semigroup theory
Reverses of the triangle inequality in Banach spaces
No full textRecent reverses for the discrete generalised triangle inequality and its continuous version for vector-valued integrals in Banach spaces are surveyed. New results are also obtained. Particular instances of interest in Hilbert spaces and for complex numbers and functions are pointed out as well
A New Proof for a Rolewicz's Type Theorem: An Evolution Semigroup Approach
No full textLet be a positive and non-decreasing function defined on the real half-line and be a strongly continuous and exponentially bounded evolution family of bounded linear operators acting on a Banach space. We prove that if and satisfy a certain integral condition (see the relation (2) below) then is uniformly exponentially stable. For continuous, this result is due to S. Rolewicz
Linear maps on real C* - algebras and related structures
No full textPhDIn this thesis we obtain new results on the structures of real C*-algebras and nonsurjective
isometries between them. Some of the results have been published in
[1].
We prove a spectral inequality for real Banach*-algebras and give characterisations
of real C*-algebras among Banach*-algebras.
We study the ideal and facial structures in real C*-algebras and show that
there is a bijection from the class of norm-closed left ideals I of a real C*-algebra
A to the class of weak*-closed faces F of the state space S(A). The bijection
is given by I 7! F = f 2 S(A) : (a a) = 0 for all a 2 Ig, with inverse
F 7! I = fa 2 A : (a a) = 0 for all 2 Fg.
As an application, we use the structures of faces to show an algebraic property
of linear maps on real C*-algebras. We prove that if T : A ! B is a linear
contraction between real C*-algebras A and B, then there is a projection p in the
second dual B00 of B such that
T(aa a)p = T(a)T(a) T(a)p (a 2 A).
If T is an isometry, not necessarily surjective, we obtain a stronger result which
also extends a celebrated result of Kadison on surjective isometries between complex
C*-algebras. We prove the following theorem.
Let T be a linear isometry between two real C*-algebras A and B, which can
be non-surjective. Then for each a 2 A there exists a partial isometry u 2 B00 and
a projection p 2 B00 such that
(i) fu; T(ff; g; hg); ug = fu; fT(f); T(g); T(h)g; ug;
(ii) T(ff; g; hg)p = fT(f); T(g); T(h)gp,
for all f; g; h in the real JB*-triple A(a) generated by a 2 A, where ff; g; hg is
the triple product defined by 2ff; g; hg = fg h + hg f. Moreover, fu; T( ):ug :
A(a) ! B00 and T( )p : A(a) ! B00 are isometries.
This theorem cannot be proved by simple complexification. We give an example
of a real linear isometry which cannot be complexified to a complex isometry.
We conclude by proving a theorem which states that a Jordan*-homomorphism
T : A ! B between real C*-algebras A and B is a sum of a C*-homomorphism
and a C*-antihomomorphism, extending a well-known result for complex C*-
algebras
On sequentially right Banach spaces
No full textIn this paper, we study the recently introduced class of sequentially Right Banach spaces. We introduce a stronger property (RD) and compare these two properties with other well-known isomorphic properties of Banach spaces such as property (V) or the Dieudonné property. In particular, we show that there is a sequentially Right Banach space without property (V). This answers a question of A.M. Peralta, I. Villanueva, J.D.M. Wright and K. Ylinen. We also generalize a result of A. Pelczy´nski and prove that every sequentially Right Banach space has weakly sequentially complete dual. Finally, it is shown that if K is a scattered compact Hausdorff space then the space C(K;X) of X-valued continuous functions on K is sequentially Right (resp. has property (RD)) if and only if X has the same property.peerReviewe
Quasianalytic Banach function algebras
No full textWe construct certain Banach algebras of infinitely differentiable functions on compact plane sets such that the algebras are quasianalytic, and we use these algebras to construct examples of Banach algebras defined on their maximal ideal spaces which, first, have only countably many peak points and, second, have the property that a discontinuous function operates on the algebra. We show that any function defined on an open subset of the plane which operates on a Banach function algebra is necessarily continuous on a dense open subset of its domain
Polynomials on Banach Spaces: Zeros and Maximal Points
No full textAbstractA maximal point of a polynomial on a Banach space is a point in the unit ball at which the polynomial attains its norm. Lower bounds are given for the distances between zeros and maximal points
Group living homes for older people with dementia: Concept and effects
No full textEefsting, J.A. [Promotor]Pot, A.M. [Promotor]Depla, M.F.I.A. [Copromotor]Lange, J. de [Copromotor
Cementbetonnen plaatbekledingen op oevers en dijken, bundeling van artikelen uit de vakpers 1990-1991
No full textCUR; Proefproject: Open colloidaal beton a/s dijkbekleding; PT civiele techniek, april 1990. Burger, A.M., Eversdijk, P.J. en Hendriksma, A.M.; Open cementbeton toegepast a/s bekleding voor dijken; Zeewering Breskens, proefproject voor colloidaal beton; Land + Water, mei 1990. Burger, A.M., Eversdijk, P.J. en Hendriksma, A.M.; Colloidaal beton weerstaat zware storm en hoge golven; De praktijk van open cementbeton a/s Plaatbekleding; Land + Water, juni 1990. CUR; Cementbetonnen plaatbekledingen op dijken; Proefprojecten CUR; Civiele Techniek, No4, 1990. Vrieze, C.G. de; Betonnen dijken, groen a/s gras; Proeven met colloidaal beton voor begroeide rivierdijken; Land + Water No.6, juni 1991. Eversdijk, P.J. en Fase, A.G.; Breuksteen met colloidaal beton pakt rivierdijken goed in; Proefproject Opijnen in Julianakanaal; Land + Water No. 7/8, augustus 1991. Rijke, W.G. de en Burger, A.M.; Cementbetonnen plaatbekledingen op dijken en oevers; Praktische ontwerpmethode (1); Civiele Techniek, jaargang 46, No.3, 1991. Rijke, W.G. de en Burger, A.M.; Cementbetonnen plaatbekledingen op dijken en oevers theoretisch waterdicht; Praktische ontwerpmethode (2); Civiele Techniek, jaargang 46, No.4, 1991. CUR; oemonstratieproject open colloidaal beton Noordoostpolder; Civiele Techniek, No.3, 1991
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