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1.
In the study of the asymptotic behaviour of solutions of differential-difference equations the
-spectrum has been useful, where
and
implies Fourier transform
, with
given
, φ∈L
∞(ℝ,X), X a Banach space,
(half)line. Here we study
and related concepts, give relations between them, especially
weak Laplace half-line spectrum of φ, and thus ⊂ classical Beurling spectrum = Carleman spectrum =
; also
= Beurling spectrum of “φ modulo
” (Chill-Fasangova). If
satisfies a Loomis type condition (L
U
), then
countable and
uniformly continuous ∈U are shown to imply
; here (L
U
) usually means
, indefinite integral Pf of f in U imply Pf in
(the Bohl-Bohr theorem for
= almost periodic functions, U=bounded functions). This spectral characterization and other results are extended to unbounded functions via mean classes
, ℳ
m
U ((2.1) below) and even to distributions, generalizing various recent results for uniformly continuous bounded φ. Furthermore for solutions of convolution systems S*φ=b with
in some
we show
. With these above results, one gets generalizations of earlier results on the asymptotic behaviour of solutions of neutral
integro-differential-difference systems. Also many examples and special cases are discussed. 相似文献
2.
Valentina Rossi 《Applied Categorical Structures》2006,14(4):291-311
Given a regular Gumm category such that any regular epimorphism is effective for descent, we prove that any Birkhoff subcategory in gives rise to an admissible Galois structure. This result allows one to consider some new applications of the categorical Galois theory in the context of topological algebras. Given a regular Mal’cev category , we first characterize the coverings of the Galois structure induced by the subcategory of the abelian objects in . Then we consider as a subcategory of the category of the equivalence relations in , and we characterize the coverings of the corresponding Galois structure . By composing the Galois structures and we obtain the Galois structure induced by as a subcategory of . We give the characterization of the -coverings in terms of the coverings of and . 相似文献
3.
J. Pohjanpelto 《BIT Numerical Mathematics》2008,48(2):337-355
A symmetry-based method for constructing solutions to systems of differential equations founded on the reduction of exterior
differential systems invariant under the action of an infinite dimensional pseudogroup is proposed. One can associate to any
system of differential equations Δ=0 with a symmetry group an exterior differential system invariant under so that solutions of Δ=0 correspond to integral manifolds . The -invariant exterior differential system gives rise to a reduced system specified on a cross section to the pseudogroup orbits, and it is shown that solutions to Δ=0 can be reconstructed from integral
manifolds by solving an equation of generalized Lie type for the jets of pseudogroup transformations. In particular, as opposed to
the classical method of symmetry reduction, every solution to the system of differential equations can, under some mild regularity
assumptions, be constructed by the present algorithm.
AMS subject classification (2000) 58A15, 58A20, 58H05, 58J70 相似文献
4.
Zhixiang Wu 《Acta Appl Math》2009,106(2):185-198
In present paper we define a new kind of weak quantized enveloping algebra
of Borcherds superalgebras
. It is a noncommutative and noncocommutative weak graded Hopf algebra. Using localizing with some Ore set, we obtain a different
kind of quantized enveloping algebras of Borcherds superalgebras
. It has a homomorphic image which is isomorphic to the usual quantum enveloping algebra
of
. Moreover,
is isomorphic to a direct sum of
and an other algebra as algebras.
The author is sponsored by ZJNSF No. Y607136. 相似文献
5.
In this paper, we study and classify Hilbert space representations of cross product -algebras of the quantized enveloping algebra with the coordinate algebras of the quantum motion group and of the complex plane, and of the quantized enveloping algebra with the coordinate algebras of the quantum group and of the quantum disc. Invariant positive functionals and the corresponding Heisenberg representations are explicitly described.Presented by S.L. Woronowicz. 相似文献
6.
Given an open set in , we prove that every function in is zero everywhere on the boundary if and only if is regular in capacity. If in addition is bounded, then it is regular in capacity if and only if the mapping from into is injective, where denotes the Perron solution of the Dirichlet problem. Let be the set of all open subsets of which are regular in capacity. Then one can define metrics and on only involving the resolvent of the Dirichlet Laplacian. Convergence in those metrics will be defined to be the local/global uniform convergence of the resolvent of the Dirichlet Laplacian applied to the constant function . We prove that the spaces and are complete and contain the set of all open sets which are regular in the sense of Wiener (or Dirichlet regular) as a closed subset. 相似文献
7.
Inspired by the work of Paterson on C
*
-algebras of directed graphs, we show how to associate a groupoid
to an ultragraph
in such a way that the C
*-algebra of
is canonically isomorphic to Tomforde’s C
*-algebra
. The groupoid
is built from an inverse semigroup
naturally associated to
.
A.E. Marrero was supported by grants from the National Science Foundation and the Sloan Foundation and by a GAANN Fellowship.
Many of the results here are taken from this author’s dissertation [7].
P.S. Muhly was supported by a grant from the National Science Foundation (DMS-0355443). 相似文献
8.
Béatrice Vedel 《Journal of Fourier Analysis and Applications》2009,15(1):101-123
We propose the construction of wavelet bases with pseudo-polynomials adapted to the homogeneous Sobolev spaces
, s−n/2∈ℕ. They provide a confinement of the infrared divergence by decomposing
as a direct sum X
⊕
Y where X is a “small” space which carries the divergence and Y can be embedded in
. In the case of
we also construct such an orthonormal basis, which provides a confinement of the Mumford process. 相似文献
9.
Emanuele Delucchi 《Journal of Algebraic Combinatorics》2007,26(4):477-494
Given a finite group G and a natural number n, we study the structure of the complex of nested sets of the associated Dowling lattice
(Proc. Internat. Sympos., 1971, pp. 101–115) and of its subposet of the G-symmetric partitions
which was recently introduced by Hultman (, 2006), together with the complex of G-symmetric phylogenetic trees
. Hultman shows that the complexes
and
are homotopy equivalent and Cohen–Macaulay, and determines the rank of their top homology.
An application of the theory of building sets and nested set complexes by Feichtner and Kozlov (Selecta Math. (N.S.)
10, 37–60, 2004) shows that in fact
is subdivided by the order complex of
. We introduce the complex of Dowling trees
and prove that it is subdivided by the order complex of
. Application of a theorem of Feichtner and Sturmfels (Port. Math. (N.S.)
62, 437–468, 2005) shows that, as a simplicial complex,
is in fact isomorphic to the Bergman complex of the associated Dowling geometry.
Topologically, we prove that
is obtained from
by successive coning over certain subcomplexes. It is well known that
is shellable, and of the same dimension as
. We explicitly and independently calculate how many homology spheres are added in passing from
to
. Comparison with work of Gottlieb and Wachs (Adv. Appl. Math.
24(4), 301–336, 2000) shows that
is intimely related to the representation theory of the top homology of
.
Research partially supported by the Swiss National Science Foundation, project PP002-106403/1. 相似文献
10.
Let be a finite-dimensional complex reductive Lie algebra and S() its symmetric algebra. The nilpotent bicone of is the subset of elements (x, y) of whose subspace generated by x and y is contained in the nilpotent cone. The nilpotent bicone is naturally endowed with a scheme structure, as nullvariety of
the augmentation ideal of the subalgebra of generated by the 2-order polarizations of invariants of . The main result of this paper is that the nilpotent bicone is a complete intersection of dimension , where and are the dimensions of Borel subalgebras and the rank of , respectively. This affirmatively answers a conjecture of Kraft and Wallach concerning the nullcone [KrW2]. In addition, we introduce and study in this paper the characteristic submodule of . The properties of the nilpotent bicone and the characteristic submodule are known to be very important for the understanding
of the commuting variety and its ideal of definition. The main difficulty encountered for this work is that the nilpotent
bicone is not reduced. To deal with this problem, we introduce an auxiliary reduced variety, the principal bicone. The nilpotent bicone, as well as the principal bicone, are linked to jet schemes. We study their dimensions using arguments
from motivic integration. Namely, we follow methods developed by Mustaţǎ in [Mu]. Finally, we give applications of our results to invariant theory. 相似文献
11.
Let be a field and q be a nonzero element of that is not a root of unity. We give a criterion for 〈0〉 to be a primitive ideal of the algebra of quantum matrices. Next, we describe all height one primes of ; these two problems are actually interlinked since it turns out that 〈0〉 is a primitive ideal of whenever has only finitely many height one primes. Finally, we compute the automorphism group of in the case where m ≠ n. In order to do this, we first study the action of this group on the prime spectrum of . Then, by using the preferred basis of and PBW bases, we prove that the automorphism group of is isomorphic to the torus when m ≠ n and (m,n) ≠ (1, 3),(3, 1).
This research was supported by a Marie Curie Intra-European Fellowship within the 6th European Community Framework Programme
and by Leverhulme Research Interchange Grant F/00158/X. 相似文献
12.
Let and be C*-dynamical systems and assume that is a separable simple C*-algebra and that α and β are *-automorphisms. Then the semicrossed products and are isometrically isomorphic if and only if the dynamical systems and are outer conjugate.
K. R. Davidson was partially supported by an NSERC grant. E. G. Katsoulis was partially supported by a summer grant from ECU 相似文献
13.
M. A. Abam M. de Berg M. Farshi J. Gudmundsson 《Discrete and Computational Geometry》2009,41(4):556-582
We introduce the concept of region-fault tolerant spanners for planar point sets and prove the existence of region-fault tolerant
spanners of small size. For a geometric graph
on a point set P and a region F, we define
to be what remains of
after the vertices and edges of
intersecting F have been removed. A
-fault tolerant
t-spanner is a geometric graph
on P such that for any convex region F, the graph
is a t-spanner for
, where
is the complete geometric graph on P. We prove that any set P of n points admits a
-fault tolerant (1+ε)-spanner of size
for any constant ε>0; if adding Steiner points is allowed, then the size of the spanner reduces to
, and for several special cases, we show how to obtain region-fault tolerant spanners of
size without using Steiner points. We also consider fault-tolerant geodesic
t
-spanners: this is a variant where, for any disk D, the distance in
between any two points u,v∈P∖D is at most t times the geodesic distance between u and v in ℝ2∖D. We prove that for any P, we can add
Steiner points to obtain a fault-tolerant geodesic (1+ε)-spanner of size
.
M.A. Abam was supported by the Netherlands’ Organisation for Scientific Research (NWO) under project no. 612.065.307 and by
the MADALGO Center for Massive Data Algorithmics, a Center of the Danish National Research Foundation.
M. de Berg was supported by the Netherlands’ Organisation for Scientific Research (NWO) under project no. 639.023.301.
M. Farshi was supported by Ministry of Science, Research and Technology of I.R. Iran.
NICTA is funded by the Australian Government as represented by the Department of Broadband, Communications and the Digital
Economy and the Australian Research Council through the ICT Centre of Excellence program. 相似文献
14.
A. Gerlo 《Applied Categorical Structures》2008,16(4):479-493
In a topological construct endowed with a proper -factorization system and a concrete functor , we study -compactness and -Hausdorff separation, where is a class of “closed morphisms” in the sense of Clementino et al. (A functional approach to general topology. In: Categorical
Foundations. Encyclopedia of Mathematics and Its Applications, vol. 97, pp. 103–163. Cambridge University Press, Cambridge,
2004), determined by Λ. In particular, we point out under which conditions on Λ, the notion of -compactness of an object of coincides with 0-compactness of the image in Prap. Our results will be illustrated by some examples: except for some well-known ones, like b-compactness of a topological space, we also capture some compactness notions that were not considered before in the literature.
In particular, we obtain a generalization of b-compactness to the setting of approach spaces. This notion is shown to play an important role in the study of uniformizability.
The author is research assistant at the Fund of Scientific Research Vlaanderen (FWO). 相似文献
15.
In [2] the subconstruct of sober approach spaces was introduced and it was shown to be a reflective subconstruct of the category of approach spaces. The main result of this paper states that moreover is firmly -reflective in for the class of epimorphic embeddings. ‘Firm -reflective’ is a notion introduced in [3] by G.C.L. Brümmer and E. Giuli and is inspired by the exemplary behaviour of the usual completion in the category of Hausdorff uniform spaces with uniformly continuous maps. It means that is -reflective in and that the reflector is such that belongs to if and only if is an isomorphism. Firm -reflectiveness implies uniqueness of completion in the sense that whenever is a map with and sober, the associated is an isomorphism. Our result generalizes the fact that in the category the subconstruct of sober topological spaces is firmly reflective for the class of b-dense embeddings in . Also firmness in some other subconstructs of will be easily obtained.A. Gerlo and C. Van Olmen are research assistants at the Fund of Scientific Research Vlaanderen (FWO). E. Vandersmissen is a research assistant supported by the FWO-grant G.0244.05. 相似文献
16.
Dmitri I. Panyushev 《Transformation Groups》2009,14(2):463-482
Let be an algebraic Lie algebra and a (generalised) Takiff algebra. Any finite-order automorphism θ of induces an automorphism of of the same order, denoted . We study invariant-theoretic properties of representations of the fixed point subalgebra of on other eigenspaces of in . We use the observation that, for special values of m, the fixed point subalgebra, , turns out to be a contraction of a certain Lie algebra associated with and θ.
To my teacher
Supported in part by R.F.B.R. grant 06-01-72550. 相似文献
17.
Let ℳ be a von Neumann factor of type II1 with a normalized trace τ. In 1983 L. G. Brown showed that to every operator T∈ℳ one can in a natural way associate a spectral distribution measure
μ
T (now called the Brown measure of T), which is a probability measure in ℂ with support in the spectrum σ(T) of T. In this paper it is shown that for every T∈ℳ and every Borel set B in ℂ, there is a unique closed T-invariant subspace
affiliated with ℳ, such that the Brown measure of
is concentrated on B and the Brown measure of
is concentrated on ℂ∖B. Moreover,
is T-hyperinvariant and the trace of
is equal to μ
T(B). In particular, if T∈ℳ has a Brown measure which is not concentrated on a singleton, then there exists a non-trivial, closed,
T-hyperinvariant subspace. Furthermore, it is shown that for every T∈ℳ the limit
exists in the strong operator topology, and the projection onto
is equal to 1[0,r](A), for every r>0.
Supported by The Danish National Research Foundation. 相似文献
18.
We prove the following statement.
Let , and let . Suppose that, for all and , the sequence satisfies the relation
where e(u) : = e2πiu
.
Then
where
q is the set of q-multiplicative functions g such that . 相似文献
19.
Shigeto Kawata 《Algebras and Representation Theory》2006,9(5):513-524
Let be a finite group, a complete discrete valuation ring of characteristic zero with residue class field of characteristic , and a block of the group ring . Suppose that is of infinite representation type and is sufficiently large to satisfy certain conditions. Let be the Auslander–Reiten quiver of and a connected component of . In this paper, we show that if contains some Heller lattices then the tree class of the stable part of is . Also, we show that has infinitely many components of type if a defect group of is neither cyclic nor a Klein four group.Presented by Jon Carlson. 相似文献
20.
Concettina Galati 《Annali di Matematica Pura ed Applicata》2009,188(2):359-368
Let be the variety of irreducible sextics with six cusps as singularities. Let be one of irreducible components of . Denoting by the space of moduli of smooth curves of genus 4, we consider the rational map sending the general point [Γ] of Σ, corresponding to a plane curve , to the point of parametrizing the normalization curve of Γ. The number of moduli of Σ is, by definition the dimension of Π(Σ). We know that
, where ρ(2, 4, 6) is the Brill–Noether number of linear series of dimension 2 and degree 6 on a curve of genus 4. We prove that both
irreducible components of have number of moduli equal to seven.
相似文献