Tuboïdes et structure analytique des distributions
Twisted crossed products of C*-algebras. II.
Twisted group C*-algebras corresponding to nilpotent discrete groups.
Twisted K-theory of differentiable stacks
Twisted spectral triples and covariant differential calculi
Connes and Moscovici recently studied "twisted" spectral triples (A,H,D) in which the commutators [D,a] are replaced by D∘a - σ(a)∘D, where σ is a second representation of A on H. The aim of this note is to point out that this yields representations of arbitrary covariant differential calculi over Hopf algebras in the sense of Woronowicz. For compact quantum groups, H can be completed to a Hilbert space and the calculus is given by bounded operators. At the end, we discuss an explicit example of...
Two characterizations of automorphisms on B(X)
Let X be an infinite-dimensional Banach space, and let ϕ be a surjective linear map on B(X) with ϕ(I) = I. If ϕ preserves injective operators in both directions then ϕ is an automorphism of the algebra B(X). If X is a Hilbert space, then ϕ is an automorphism of B(X) if and only if it preserves surjective operators in both directions.
Two complete and minimal systems associated with the zeros of the Riemann zeta function
We link together three themes which had remained separated so far: the Hilbert space properties of the Riemann zeros, the “dual Poisson formula” of Duffin-Weinberger (also named by us co-Poisson formula), and the “Sonine spaces” of entire functions defined and studied by de Branges. We determine in which (extended) Sonine spaces the zeros define a complete, or minimal, system. We obtain some general results dealing with the distribution of the zeros of the de-Branges-Sonine entire functions. We...
Two complex variants of a Hankel type transformation of generalized functions
Two endpoint bounds for generalized Radon transforms in the plane.
Two examples of non-separable metrizable spaces
Two Families of Self-adjoint Indecomposable Operators in an Orthomodular Space
Orthomodular spaces are the counterpart of Hilbert spaces for fields other than or . Both share numerous properties, foremost among them is the validity of the Projection theorem. Nevertheless in the study of bounded linear operators which started in [3], there appeared striking differences with the classical theory. In fact, in this paper we shall construct, on the canonical non-archimedean orthomodular space of [5], two infinite families of self-adjoint bounded linear operators having no...
Two fixed-point theorems for mappings satisfying a general contractive condition of integral type in the modular space.
Two generalizations of Komlós' theorem with lower closure-type applications.
Two geometric constants for operators acting on a separable Banach space.
The main result of this paper is the following: A separable Banach space X is reflexive if and only if the infimum of the Gelfand numbers of any bounded linear operator defined on X can be computed by means of just one sequence on nested, closed, finite codimensional subspaces with null intersection.
Two large subsets of a functional space.
Two mappings related to semi-inner products and their applications in geometry of normed linear spaces
In this paper we introduce two mappings associated with the lower and upper semi-inner product and and with semi-inner products (in the sense of Lumer) which generate the norm of a real normed linear space, and study properties of monotonicity and boundedness of these mappings. We give a refinement of the Schwarz inequality, applications to the Birkhoff orthogonality, to smoothness of normed linear spaces as well as to the characterization of best approximants.
Two New Classes of Locally Convex Spaces.
Two observations on a theorem by Coifman
Two point boundary value problems for linear third order differential equations in the Colombeau algebra
Two problems of Calderón-Zygmund theory on product-spaces
R. Fefferman has shown that, on a product-space with two factors, an operator T bounded on maps into BMO of the product if the mean oscillation on a rectangle R of the image of a bounded function supported out of a multiple R’ of R, is dominated by , for some . We show that this result does not extend in general to the case where E has three or more factors but remains true in this case if in addition T is a convolution operator, provided . We also show that the Calderon-Coifman bicommutators,...