Approximation Properties of the Mn-Operators. (Short Communication).
Approximation theoretical properties of M-ideals (Abstract)
Approximationszahlen, p-nukleare Operatoren und Hilbertraumcharakterisierungen.
Arbitrage and pricing in a general model with flows
We study a fundamental issue in the theory of modeling of financial markets. We consider a model where any investment opportunity is described by its cash flows. We allow for a finite number of transactions in a finite time horizon. Each transaction is held at a random moment. This places our model closer to the real world situation than discrete-time or continuous-time models. Moreover, our model creates a general framework to consider markets with different types of imperfection: proportional...
Arbres dont toutes les branches sont faiblement Cauchy
Arens Semi-Regular Banach Algebras.
Arens-regularity of algebras arising from tensor norms.
Aspects of unconditionality of bases in spaces of compact operators
E. Tutaj has introduced classes of Schauder bases termed "unconditional-like" (UL) and "unconditional-like*" (UL*) whose intersection is the class of unconditional bases. In view of this association with unconditional bases, it is interesting to note that there exist Banach spaces which have no unconditional basis and yet have a basis of one of these two types (e.g., the space 𝓞[0,1]). In the same spirit, we show in this paper that the space of all compact operators on a reflexive Banach space...
Asplund Functions and Projectional Resolutions of the Identity
*Supported by the Grants AV ˇCR 101-97-02, 101-90-03, GA ˇCR 201-98-1449, and by the Grant of the Faculty of Civil Engineering of the Czech Technical University No. 2003.We further develop the theory of the so called Asplund functions, recently introduced and studied by W. K. Tang. Let f be an Asplund function on a Banach space X. We prove that (i) the subspace Y := sp ∂f(X) has a projectional resolution of the identity, and that (ii) if X is weakly Lindel¨of determined, then X admits a projectional...
Asplund operators and holomorphic maps.
Asplund spaces
Asplund spaces for beginners
Asymptotic periodicity of the iterates of positive contractions on Banach lattices
Asymptotic products and enlargibility of Banach-Lie algebras.
Asymptotic uniform moduli and Kottman constant of Orlicz sequence spaces.
Asymptotically isometric copies of c0 and l1 in quotients of Banach spaces.
Let X be a real Banach space that does not contain a copy of l1. Then X* contains asymptotically isometric copies of l1 if and only if X has a quotient which is asymptotically isometric to c0.
Attractors and asymptotic periodicity of positive operators on Banach lattices.
Averages of uniformly continuous retractions
Let X be an infinite-dimensional complex normed space, and let B and S be its closed unit ball and unit sphere, respectively. We prove that the identity map on B can be expressed as an average of three uniformly retractions of B onto S. Moreover, for every 0≤ r < 1, the three retractions are Lipschitz on rB. We also show that a stronger version where the retractions are required to be Lipschitz does not hold.
Averaging at any level.
-spaces and applications to extrapolation theory
We investigate a scale of -spaces defined with the help of certain Lorentz norms. The results are applied to extrapolation techniques concerning operators defined on adapted sequences. Our extrapolation works simultaneously with two operators, starts with --estimates, and arrives at --estimates, or more generally, at estimates between K-functionals from interpolation theory.