Compactness criteria for semigroups, a note on a preceding paper.
Compactness in Wiener amalgams on locally compact groups.
Compactness properties of a locally compact group and analytic semigroups in the group algebra.
Let G be a locally compact group with left Haar measure μ, and let L1(G) be the convolution Banach algebra of integrable functions on G with respect to μ. In this paper we are concerned with the investigation of the structure of G in terms of analytic semigroups in L1(G).
Comparison of Hausdorff measures with respect to the Euclidean and the Heisenberg metric.
We compare the Hausdorff measures and dimensions with respect to the Euclidean and Heisenberg metrics on the first Heisenberg group. The result is a dimension jump described by two inequalities. The sharpness of our estimates is shown by examples. Moreover a comparison between Euclidean and H-rectifiability is given.
Comparison theorem between Fourier transform and Fourier transform with compact support
We prove a comparison theorem between Fourier transform without support and and Fourier transform with compact support in the context of arithmetic -modules.
Comparisons of Sidon and sets
Compensated compactness and the Heisenberg group.
Compensated compactness and the Heisenberg group.
Complemented ideals of group algebras
The existence of a projection onto an ideal I of a commutative group algebra depends on its hull Z(I) ⊆ Ĝ. Existing methods for constructing a projection onto I rely on a decomposition of Z(I) into simpler hulls, which are then reassembled one at a time, resulting in a chain of projections which can be composed to give a projection onto I. These methods are refined and examples are constructed to show that this approach does not work in general. Some answers are also given to previously asked...
Complemented *-primitive Ideals in L1-algebras of Exponential Lie Groups and of Motion Groups.
Complemented Subspaces of L... (G), Ideals of L... (G) and Amenability.
Completely bounded lacunary sets for compact non-abelian groups
In this paper, we introduce and study the notion of completely bounded sets ( for short) for compact, non-abelian groups G. We characterize sets in terms of completely bounded multipliers. We prove that when G is an infinite product of special unitary groups of arbitrarily large dimension, there are sets consisting of representations of unbounded degree that are sets for all p < ∞, but are not for any p ≥ 4. This is done by showing that the space of completely bounded multipliers...
Completely bounded multipliers of the Fourier algebra of a simple Lie group of real rank one.
Completely monotone functions of finite order and Agler's conditions
Motivated by some structural properties of Drury-Arveson d-shift, we investigate a class of functions consisting of polynomials and completely monotone functions defined on the semi-group ℕ of non-negative integers, and its operator-theoretic counterpart which we refer to as the class of completely hypercontractive tuples of finite order. We obtain a Lévy-Khinchin type integral representation for the spherical generating tuples associated with such operator tuples and discuss its applications.
Completely positive maps on Coxeter groups, deformed commutation relations, and operator spaces.
Complex Hadamard matrices and the spectral set conjecture.
By analyzing the connection between complex Hadamard matrices and spectral sets, we prove the direction "spectral ⇒ tile" of the Spectral Set Conjecture, for all sets A of size |A| ≤ 5, in any finite Abelian group. This result is then extended to the infinite grid Zd for any dimension d, and finally to Rd.
Complex powers and asymptotic expansions. I. Functions of certain types.
Complex powers and asymptotic expansions. II.
Complex Unconditional Metric Approximation Property for spaces
We study the Complex Unconditional Metric Approximation Property for translation invariant spaces of continuous functions on the circle group. We show that although some “tiny” (Sidon) sets do not have this property, there are “big” sets Λ for which has (ℂ-UMAP); though these sets are such that contains functions which are not continuous, we show that there is a linear invariant lifting from these spaces into the Baire class 1 functions.
Complexité de la famille des ensembles de synthèse d'un groupe abélien localement compact
On montre que si G est un groupe abélien localment compact non diskret à base dénombrable d'ouverts, alors la famille des fermés de synthèse pour l'algèbre de Fourier A(G) est une partie coanalytique non borélienne de ℱ(G), l'ensemble des fermés de G muni de la structure borélienne d'Effros. On généralise ainsi un résultat connu dans le cas du groupe 𝕋.