Operators commuting with mixing sequences
Ha, M. D.
Illinois J. Math., Tome 43 (1999) no. 3, p. 427-446 / Harvested from Project Euclid
Let $(X,\mathcal{F} ,\mu)$ be a probability space and let $L^{2}(X,0)$ be the collection of all $f \in L^{2}(X)$ with zero integrals. A collection $\mathcal{A}$ of linear operators on $L^{2}(X)$ is said to satisfy the Gaussian-distribution property (G.D.P.) if $L^{2}(X,0)$ is invariant under $\mathcal{A}$ and there exists a constant $C \lt \infty$ such that the following condition holds: ¶ Whenever $T_{1},\ldots,T_{k}$ are finitely many operators in $\mathcal{A}$, and $f$ is a function in $L_{2}$ with zero integral, then, for any required degree of approximation, there is another $L_{2}$-function $g$ with $||g||_{2} \leq C ||f||_{2}$, such that all the inner products $(\mathrm{Re} T_{i}g, \mathrm{Re} T_{j}g)$ are approximately equal to the corresponding inner products $(\mathrm{Re} T_{i}f, \mathrm{Re} T_{j}f)$ for all $1 \leq i,j \leq k$ and such that the joint distribution of the functions $\mathrm{Re} T_{1}g,\ldots,\mathrm{Re} T_{k}g$ is approximately Gaussian. ¶ It has been proved that if $(S_{n})^{\infty}_{1}$ is a sequence of uniformly bounded linear operators on $L^{2}(X)$ that satisfies the Bourgain's infinite entropy condition and the G.D.P., then there exists an $h \in L^{2}(X)$ such that $\liminf S_{n}\,h$ fails to exist $\mu$-a.e., as a finite limit on $X$. ¶ The purpose of this paper is to provide sufficient conditions for a collection $\mathcal{A}$ of linear operators on $L^{2}(X)$ to satisfy the G.D.P.
Publié le : 1999-09-15
Classification:  47A35,  28D05,  37A30,  60F05
@article{1255985100,
     author = {Ha, M. D.},
     title = {Operators commuting with mixing sequences},
     journal = {Illinois J. Math.},
     volume = {43},
     number = {3},
     year = {1999},
     pages = { 427-446},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1255985100}
}
Ha, M. D. Operators commuting with mixing sequences. Illinois J. Math., Tome 43 (1999) no. 3, pp.  427-446. http://gdmltest.u-ga.fr/item/1255985100/