A new estimate in optimal mass transport

Let be a bounded Lipschitz regular open subset of and let be two probablity measures on . It is well known that if is absolutely continuous, then there exists, for every , a unique transport map pushing forward on and which realizes the Monge-Kantorovich distance . In this paper, we establish an bound for the displacement map which depends only on , on the shape of and on the essential infimum of the density .

     

-isomorphisms, Jordan isomorphisms, and numerical range preserving maps

Let or , where is the algebra of a bounded linear operator acting on the Hilbert space , and is the set of self-adjoint operators in . Denote the numerical range of by It is shown that a surjective map satisfies

if and only if there is a unitary operator such that has the form

where is the transpose of with respect to a fixed orthonormal basis. In other words, the map or is a -isomorphism on and a Jordan isomorphism on . Moreover, if has finite dimension, then the surjective assumption on can be removed.

     

planes in

We establish a homeomorphism between the moduli space of ordered -tuples of 2-dimensional linear subspaces (mod ) and the quotient by simultaneous conjugation of a certain open subset . For , this leads to an explicit computation of the moduli space of central 2-arrangements in mod and its subspace of those classes that contain a complex hyperplane arrangement.

     

A sharp result on -covers

Let be a finite system of residue classes which forms an -cover of (i.e., every integer belongs to at least members of ). In this paper we show the following sharp result: For any positive integers and , if there is such that the fractional part of is , then there are at least such subsets of . This extends an earlier result of M. Z. Zhang and an extension by Z. W. Sun. Also, we generalize the above result to -covers of the integral ring of any algebraic number field with a power integral basis.

     

Some Hopf Galois structures arising from elementary abelian -groups

Let be an odd prime, , the elementary abelian -group of rank , and let be the group of principal units of the ring . If is a Galois extension with Galois group , then we show that for , the number of Hopf Galois structures on afforded by -Hopf algebras with associated group is greater than , where .

     

The -local -homology of

In this paper, we introduce a Hopf algebra, developed by the author and André Henriques, which is usable in the computation of the -homology of a space. As an application, we compute the -homology of in a manner analogous to Mahowald and Milgram's computation of the -homology .

     

A note on -intersection bodies

The concept of an intersection body is central for the dual Brunn-Minkowski theory and has also played an important role in the solution of the Busemann-Petty problem. A more general concept of -intersection bodies is related to the generalization of the Busemann-Petty problem. In this note, we compare classes of -intersection bodies for different and examine the conjecture that these classes increase with . In particular, we construct a -intersection body that is not a -intersection body.

     

Semiprime smash products and -stable prime radicals for PI-algebras

Assume that is a finite-dimensional Hopf algebra over a field and that is an -module algebra satisfying a polynomial identity (PI). We prove that if is semisimple and is -semiprime, then is semiprime. If is cosemisimple, we show that the prime radical of is -stable.

     

The geography of symplectic -manifolds with an arbitrary fundamental group

In this article, for each finitely presented group , we construct a family of minimal symplectic -manifolds with which cover most lattice points with large in the region . Furthermore, we show that all these -manifolds admit infinitely many distinct smooth structures.

     

The atomic decomposition in

In this paper we present an atomic decomposition of integrable functions. As an application we compute the distance of in to the Hardy space .

     

Form estimates for the -Laplacean

We consider the problem of establishing conditions on that ensure that the form associated with the -Laplacean is positive bounded below. It was shown recently by Fan, Zhang and Zhao that - unlike the constant case - this is not possible if has a strict extrema in the domain. They also considered the closely related problem of eigenvalue existence and estimates. Our main tool is the adaptation of a technique, employed by Protter for involving arbitrary vector fields. We also examine related results obtained by a variant of Picone Identity arguments. We directly consider problems in with and while we focus on Dirichlet boundary conditions we also indicate how our approach can be used in cases of mixed boundary conditions, of unbounded domains and of discontinuous Our basic criteria involve restrictions on and its gradient.

     

Dimension des familles de courbes lisses sur une surface quartique normale de

Dans cette note, on montre que les courbes, lisses connexes, de degré et genre , tracées sur une surface quartique normale variable de , et n'y étant pas intersection complète, forment des familles de dimensions . Cette majoration est la meilleure possible. Comme application on prouve que le schéma de Hilbert des courbes lisses connexes de de degré et genre est irréductible.

     

A short proof of Bing's characterization of

We give a short proof of Bing's characterization of : a compact, connected 3-manifold is if and only if every knot in is isotopic into a ball.

     

On pointed Hopf algebras associated to some conjugacy classes in

We show that any pointed Hopf algebra with infinitesimal braiding associated to the conjugacy class of is infinite-dimensional, if either the order of is odd, or all cycles in the decomposition of as a product of disjoint cycles have odd order except for exactly two transpositions.

     

The problem of minimizing locally a functional around non-critical points is well-posed

In this paper, we prove the following general result: Let be a real Hilbert space and a functional, with locally Lipschitzian derivative.

Then, for each with , there exists such that, for every , the restriction of to the sphere has a unique global minimum toward which every minimizing sequence strongly converges.

     

A condition under which follows from

We will give some sufficient conditions for a -hyponormal operator, , to be normal, and a sufficient condition for a triplet of operators , , with , self-adjoint and unitary such that necessarily satisfies .

     

A reduction theorem for the topological degree for mappings of class

The reduction theorem for the Leray-Schauder degree provides an efficient tool to calculate the value of the degree in a suitable invariant subspace. We shall prove how the calculation of the value of the topological degree for a mapping of class from a real separable reflexive Banach space into the dual space can be reduced into the calculation of degree of mapping from a closed subspace into Since the Leray-Schauder mappings are acting from to and we are dealing with mappings from to the standard `invariant subspace' condition must be replaced by a less obvious one.

     

On the index and spectrum of differential operators on

If is an system of differential operators on having continuous coefficients with vanishing oscillation at infinity, the Cordes-Illner theory ensures that is Fredholm from to for all or no value We prove that both the index (when defined) and the spectrum of are independent of

     

Embeddings of -dimensional separable metric spaces into the product of Sierpinski curves

We give a short proof of the following fact: the set of embeddings of any -dimensional separable metric space into a certain -dimensional subset of the -product of Sierpinski curves is residual in .

     

Random series in using unconditional basic sequences and stable sequences: A result on almost sure almost everywhere convergence

Here we study the almost sure almost everywhere convergence of random series of the form in the Lebesgue spaces , where the 's are centered random variables, and the 's constitute an unconditional basic sequence or an stable sequence. We show that if one of these series converges in the norm topology almost surely, then it converges almost everywhere almost surely.