Displaying 61 – 80 of 103

Showing per page

Some results on packing in Orlicz sequence spaces

Y. Q. Yan (2001)

Studia Mathematica

We present monotonicity theorems for index functions of N-fuctions, and obtain formulas for exact values of packing constants. In particular, we show that the Orlicz sequence space l ( N ) generated by the N-function N(v) = (1+|v|)ln(1+|v|) - |v| with Luxemburg norm has the Kottman constant K ( l ( N ) ) = N - 1 ( 1 ) / N - 1 ( 1 / 2 ) , which answers M. M. Rao and Z. D. Ren’s [8] problem.

Some Structures Related to Metric Projections in Orlicz Spaces

Bor-Luh Lin, Zhongrui Shi (1999)

Colloquium Mathematicae

We discuss k-rotundity, weak k-rotundity, C-k-rotundity, weak C-k-rotundity, k-nearly uniform convexity, k-β property, C-I property, C-II property, C-III property and nearly uniform convexity both pointwise and global in Orlicz function spaces equipped with Luxemburg norm. Applications to continuity for the metric projection at a given point are given in Orlicz function spaces with Luxemburg norm.

Space of Baire functions. I

J. E. Jayne (1974)

Annales de l'institut Fourier

Several equivalent conditions are given for the existence of real-valued Baire functions of all classes on a type of K -analytic spaces, called disjoint analytic spaces, and on all pseudocompact spaces. The sequential stability index for the Banach space of bounded continuous real-valued functions on these spaces is shown to be either 0 , 1 , or Ω (the first uncountable ordinal). In contrast, the space of bounded real-valued Baire functions of class 1 is shown to contain closed linear subspaces with index...

Spaces defined by the level function and their duals

Gord Sinnamon (1994)

Studia Mathematica

The classical level function construction of Halperin and Lorentz is extended to Lebesgue spaces with general measures. The construction is also carried farther. In particular, the level function is considered as a monotone map on its natural domain, a superspace of L p . These domains are shown to be Banach spaces which, although closely tied to L p spaces, are not reflexive. A related construction is given which characterizes their dual spaces.

Spaces of measurable functions

Piotr Niemiec (2013)

Open Mathematics

For a metrizable space X and a finite measure space (Ω, 𝔐 , µ), the space M µ(X) of all equivalence classes (under the relation of equality almost everywhere mod µ) of 𝔐 -measurable functions from Ω to X, whose images are separable, equipped with the topology of convergence in measure, and some of its subspaces are studied. In particular, it is shown that M µ(X) is homeomorphic to a Hilbert space provided µ is (nonzero) nonatomic and X is completely metrizable and has more than one point.

Stable points of unit ball in Orlicz spaces

Marek Wisła (1991)

Commentationes Mathematicae Universitatis Carolinae

The aim of this paper is to investigate stability of unit ball in Orlicz spaces, endowed with the Luxemburg norm, from the “local” point of view. Firstly, those points of the unit ball are characterized which are stable, i.e., at which the map z { ( x , y ) : 1 2 ( x + y ) = z } is lower-semicontinuous. Then the main theorem is established: An Orlicz space L ϕ ( μ ) has stable unit ball if and only if either L ϕ ( μ ) is finite dimensional or it is isometric to L ( μ ) or ϕ satisfies the condition Δ r or Δ r 0 (appropriate to the measure μ and the function...

Strictly singular inclusions of rearrangement invariant spaces and Rademacher spaces

Sergei V. Astashkin, Francisco L. Hernández, Evgeni M. Semenov (2009)

Studia Mathematica

If G is the closure of L in exp L₂, it is proved that the inclusion between rearrangement invariant spaces E ⊂ F is strictly singular if and only if it is disjointly strictly singular and E ⊊ G. For any Marcinkiewicz space M(φ) ⊂ G such that M(φ) is not an interpolation space between L and G it is proved that there exists another Marcinkiewicz space M(ψ) ⊊ M(φ) with the property that the M(ψ) and M(φ) norms are equivalent on the Rademacher subspace. Applications are given and a question of Milman...

Currently displaying 61 – 80 of 103