Expand all Collapse all  Results 26  35 of 35 
26. CMB 2002 (vol 45 pp. 483)
Diffraction of Weighted Lattice Subsets A Dirac comb of point measures in Euclidean space with bounded
complex weights that is supported on a lattice $\varGamma$ inherits
certain general properties from the lattice structure. In
particular, its autocorrelation admits a factorization into a
continuous function and the uniform lattice Dirac comb, and its
diffraction measure is periodic, with the dual lattice
$\varGamma^*$ as lattice of periods. This statement remains true
in the setting of a locally compact Abelian group whose topology
has a countable base.
Keywords:diffraction, Dirac combs, lattice subsets, homometric sets Categories:52C07, 43A25, 52C23, 43A05 
27. CMB 2002 (vol 45 pp. 436)
The Spherical Functions Related to the Root System $B_2$ In this paper, we give an integral formula for the eigenfunctions of
the ring of differential operators related to the root system $B_2$.
Categories:43A90, 22E30, 33C80 
28. CMB 2001 (vol 44 pp. 231)
Weak Convergence Is Not Strong Convergence For Amenable Groups Let $G$ be an infinite discrete amenable group or a nondiscrete
amenable group. It is shown how to construct a net $(f_\alpha)$ of
positive, normalized functions in $L_1(G)$ such that the net converges weak*
to invariance but does not converge strongly to invariance. The solution of
certain linear equations determined by colorings of the Cayley graphs of the
group are central to this construction.
Category:43A07 
29. CMB 2000 (vol 43 pp. 330)
Maximal Operators and Cantor Sets We consider maximal operators in the plane, defined by Cantor sets of
directions, and show such operators are not bounded on $L^2$ if the
Cantor set has positive Hausdorff dimension.
Keywords:maximal functions, Cantor set, lacunary set Categories:42B25, 43A46 
30. CMB 1999 (vol 42 pp. 169)
Heat Kernels of Lorentz Cones We obtain an explicit formula for heat kernels of Lorentz cones, a
family of classical symmetric cones. By this formula, the heat
kernel of a Lorentz cone is expressed by a function of time $t$ and
two eigenvalues of an element in the cone. We obtain also upper and
lower bounds for the heat kernels of Lorentz cones.
Keywords:Lorentz cone, symmetric cone, Jordan algebra, heat kernel, heat equation, LaplaceBeltrami operator, eigenvalues Categories:35K05, 43A85, 35K15, 80A20 
31. CMB 1998 (vol 41 pp. 392)
A note on $H^1$ multipliers for locally compact Vilenkin groups Kitada and then Onneweer and Quek have investigated multiplier
operators on Hardy spaces over locally compact Vilenkin groups. In
this note, we provide an improvement to their results for the Hardy
space $H^1$ and provide examples showing that our result applies to a
significantly larger group of multipliers.
Categories:43A70, 44A35 
32. CMB 1997 (vol 40 pp. 316)
On geometric properties of OrliczLorentz spaces Criteria for local uniform rotundity and midpoint local uniform
rotundity in OrliczLorentz spaces with the Luxemburg norm are given.
Strict $K$monotonicity and KadecKlee property are also discussed.
Category:43B20 
33. CMB 1997 (vol 40 pp. 296)
A general approach to LittlewoodPaley theorems for orthogonal families A general lacunary LittlewoodPaley type theorem is proved, which applies in a
variety of settings including Jacobi polynomials in $[0, 1]$, $\su$, and the
usual classical trigonometric series in $[0, 2 \pi)$. The theorem is used to
derive new results for $\LP$ multipliers on $\su$ and Jacobi $\LP$ multipliers.
Categories:42B25, 42C10, 43A80 
34. CMB 1997 (vol 40 pp. 183)
The range of group algebra homomorphisms A characterisation of the range of a homomorphism between two
commutative group algebras is presented which implies, among other
things, that this range is closed. The work relies mainly on the
characterisation of such homomorphisms achieved by P.~J.~Cohen.
Categories:43A22, 22B10, 46J99 
35. CMB 1997 (vol 40 pp. 133)
Derivations from totally ordered semigroup algebras into their duals For a wellbehaved measure $\mu$, on a locally compact
totally ordered set $X$, with continuous part $\mu_c$, we make
$L^p(X,\mu_c)$
into a commutative Banach bimodule over the totally ordered
semigroup algebra
$L^p(X,\mu)$, in such a way that the natural surjection from the algebra
to the module is a bounded derivation. This gives rise to bounded
derivations from $L^p(X,\mu)$
into its dual module and in particular shows that if $\mu_c$ is not
identically zero then $L^p(X,\mu)$ is not weakly
amenable. We show that all bounded derivations from $L^1(X,\mu)$
into its dual module arise in this way and also describe all bounded
derivations from
$L^p(X,\mu)$ into its dual for $1
