Search
Search results for
We found
4 results for you
-
The Umd Constants of the Summation Operators
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Jörg WenzelThe UMD property of a Banach space is one of the most useful properties when one thinks about possible applications. This is in particular due to the boundedness of the vector-valued Hilbert transform for functions with values in such a... -
A note on regular martingales in Riesz spaces
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Mareli Korostenski CoenraadC.A. LabuschagneWe consider regular martingales (i.e., martingales which can be written as differences of two positive martingales) in the measure-free setting of Riesz spaces. The aim of this note is to show that the space of such martingales is a Riesz... -
Doob's decomposition of set-valued submartingales via ordered near vector spaces
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: CoenraadC.A. Labuschagne AndrewL. PinchuckWe use ideas from measure-free martingale theory and Rådström's completion of a near vector space to derive a Doob decomposition of submartingales in ordered near vector spaces. As a special cases thereof, we obtain the Doob decomposition of set-valued submartingales,... -
Some properties of the Walsh-Nörlund means
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Ushangi Goginava --- United Arab Emirates University, UAE Károly Nagy --- Institute of Mathematics and Computer Sciences, University of Nyíregyháza, Nyíregyháza, HungaryIn the present paper we give a necessary and sufficient condition on monotone weights, which guaranties the Nörlund means of Walsh-Fourier series converge in L 1 norm and CW norm. We also discuss the almost everywhere summability by Nörlund means...