6533b81ffe1ef96bd12771ea

RESEARCH PRODUCT

Operator martingale decomposition and the Radon-Nikodym property in Banach spaces

Coenraad C.a. LabuschagneValeria Marraffa

subject

Uniform amartPure mathematicsDinculeanu operatorApproximation propertyEberlein–Šmulian theoremBanach spaceRadon–Nikodým propertyFinite-rank operatorBanach manifoldBanach lattice Banach space Bochner norm Cone absolutely summing operator Convergent martingale Convergent submartingale Dinculeanu operator Radon–Nikodým propertySettore MAT/05 - Analisi MatematicaLp spaceC0-semigroupBanach lattice Banach space Bochner norm Cone absolutely summing operator Convergent martingale Convergent submartingale Dinculeanu operator Radon–Nikodým property Uniform amartMathematicsDiscrete mathematicsMathematics::Functional AnalysisBanach spaceApplied MathematicsConvergent martingaleConvergent submartingaleBanach latticeBochner normCone absolutely summing operatorBounded functionAnalysis

description

Abstract We consider submartingales and uniform amarts of maps acting between a Banach lattice and a Banach lattice or a Banach space. In this measure-free setting of martingale theory, it is known that a Banach space Y has the Radon–Nikodým property if and only if every uniformly norm bounded martingale defined on the Chaney–Schaefer l-tensor product E ⊗ ˜ l Y , where E is a suitable Banach lattice, is norm convergent. We present applications of this result. Firstly, an analogues characterization for Banach lattices Y with the Radon–Nikodým property is given in terms of a suitable set of submartingales (supermartingales) on E ⊗ ˜ l Y . Secondly, we derive a Riesz decomposition for uniform amarts of maps acting between a Banach lattice and a Banach space. This result is used to characterize Banach spaces with the Radon–Nikodým property in terms of uniformly norm bounded uniform amarts of maps that are norm convergent. In the case 1 p ∞ , our results yield L p ( μ , Y ) -space analogues of some of the well-known results on uniform amarts in L 1 ( μ , Y ) -spaces.

10.1016/j.jmaa.2009.08.054http://hdl.handle.net/10447/44620