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1.
Masanori Katsurada 《The Ramanujan Journal》2007,14(2):249-275
Let Q(u,v)=|u+vz|2 be a positive-definite quadratic form with a complex parameter z=x+iy in the upper-half plane. The Epstein zeta-function attached to Q is initially defined by
for Re s>1, where the term with m=n=0 is to be omitted. We deduce complete asymptotic expansions of
as y→+∞ (Theorem 1 in Sect. 2), and of its weighted mean value (with respect to y) in the form of a Laplace-Mellin transform of
(Theorem 2 in Sect. 2). Prior to the proofs of these asymptotic expansions, the meromorphic continuation of
over the whole s-plane is prepared by means of Mellin-Barnes integral transformations (Proposition 1 in Sect. 3). This procedure, differs
slightly from other previously known methods of the analytic continuation, gives a new alternative proof of the Fourier expansion
of
(Proposition 2 in Sect. 3). The use of Mellin-Barnes type of integral formulae is crucial in all aspects of the proofs; several
transformation properties of hypergeometric functions are especially applied with manipulation of these integrals.
Research supported in part by Grant-in-Aid for Scientific Research (No. 13640041), the Ministry of Education, Culture, Sports,
Science and Technology of Japan. 相似文献
2.
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
3.
Dongho Byeon 《The Ramanujan Journal》2009,19(1):71-77
We shall show that the number of quadratic fields with absolute discriminant ≤x and noncyclic 5- or 7-class group is ≫x
1/4 improving the existing known bound
for g=5 and
for g=7 in Byeon (Ramanujan J. 11:159–163, 2006).
This work was supported by KRF-2005-070-C00004. 相似文献
4.
Libor Barto 《Applied Categorical Structures》2009,17(2):119-152
This paper is a contribution to the theory of functor slices of J. Sichler and V. Trnková. For every ordinal α we introduce a basket , prove that every essentially algebraic category of height α is a slice of , characterize small slices of and give a common generalization of known results about slices of the algebraic basket .
相似文献
5.
Saugata Basu 《Discrete and Computational Geometry》2008,40(4):481-503
Let
be an o-minimal structure over ℝ,
a closed definable set, and
the projection maps as depicted below:
For any collection
of subsets of
, and
, let
denote the collection of subsets of
where
. We prove that there exists a constant C=C(T)>0 such that for any family
of definable sets, where each A
i
=π
1(T∩π
2−1(y
i
)), for some y
i
∈ℝ
ℓ
, the number of distinct stable homotopy types amongst the arrangements
is bounded by
while the number of distinct homotopy types is bounded by
This generalizes to the o-minimal setting, bounds of the same type proved in Basu and Vorobjov (J. Lond. Math. Soc. (2) 76(3):757–776,
2007) for semi-algebraic and semi-Pfaffian families. One technical tool used in the proof of the above results is a pair of topological
comparison theorems reminiscent of Helly’s theorem in convexity theory. These theorems might be of independent interest in
the quantitative study of arrangements.
The author was supported in part by NSF grant CCF-0634907. 相似文献
6.
N. Bergeron 《Transformation Groups》2009,14(1):41-86
Let G be a connected semisimple group over . Given a maximal compact subgroup K ⊂ G() such that X = G()/K is a Hermitian symmetric domain, and a convenient arithmetic subgroup Γ ⊂ G(), one constructs a (connected) Shimura variety S = S(Γ) = Γ\X. If H ⊂ G is a connected semisimple subgroup such that H() / K is maximal compact, then Y = H()/K is a Hermitian symmetric subdomain of X. For each g ∈ G() one can construct a connected Shimura variety S(H, g) = (H() ∩ g
−1Γg)\Y and a natural holomorphic map j
g
: S(H, g) → S induced by the map H() → G(), h → gh. Let us assume that G is anisotropic, which implies that S and S(H, g) are compact. Then, for each positive integer k, the map j
g
induces a restriction map
In this paper we focus on classical Hermitian domains and give explicit criterions for the injectivity of the product of the
maps R
g
(for g running through G()) when restricted to the strongly primitive (in the sense of Vogan and Zuckerman) part of the cohomology. In the holomorphic
case we recover previous results of Clozel and Venkataramana [CV]. We also derive applications of our results to the proofs
of new cases of the Hodge conjecture and of new results on the vanishing of the cohomology of some particular Shimura variety. 相似文献
7.
Let M be either or . We construct the first example of a simply-connected irreducible symplectic 4-manifold that is homeomorphic but not diffeomorphic
to M.
Dedicated to Ronald J. Stern on the occasion of his sixtieth birthday
Mathematics Subject Classification (2000) Primary 57R55; Secondary 57R17, 57M05 相似文献
8.
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
9.
Roy Meshulam 《Order》2008,25(2):153-155
Let L be a finite lattice and let . It is shown that if the order complex satisfies then |L| ≥ 2
k
. Equality |L| = 2
k
holds iff L is isomorphic to the Boolean lattice {0,1}
k
.
Research supported by the Israel Science Foundation. 相似文献
10.
This paper generalizes the mixed extension principle in L
2(ℝ
d
) of (Ron and Shen in J. Fourier Anal. Appl. 3:617–637, 1997) to a pair of dual Sobolev spaces H
s
(ℝ
d
) and H
−s
(ℝ
d
). In terms of masks for φ,ψ
1,…,ψ
L
∈H
s
(ℝ
d
) and
, simple sufficient conditions are given to ensure that (X
s
(φ;ψ
1,…,ψ
L
),
forms a pair of dual wavelet frames in (H
s
(ℝ
d
),H
−s
(ℝ
d
)), where
For s>0, the key of this general mixed extension principle is the regularity of φ, ψ
1,…,ψ
L
, and the vanishing moments of
, while allowing
,
to be tempered distributions not in L
2(ℝ
d
) and ψ
1,…,ψ
L
to have no vanishing moments. So, the systems X
s
(φ;ψ
1,…,ψ
L
) and
may not be able to be normalized into a frame of L
2(ℝ
d
). As an example, we show that {2
j(1/2−s)
B
m
(2
j
⋅−k):j∈ℕ0,k∈ℤ} is a wavelet frame in H
s
(ℝ) for any 0<s<m−1/2, where B
m
is the B-spline of order m. This simple construction is also applied to multivariate box splines to obtain wavelet frames with short supports, noting
that it is hard to construct nonseparable multivariate wavelet frames with small supports. Applying this general mixed extension
principle, we obtain and characterize dual Riesz bases
in Sobolev spaces (H
s
(ℝ
d
),H
−s
(ℝ
d
)). For example, all interpolatory wavelet systems in (Donoho, Interpolating wavelet transform. Preprint, 1997) generated by an interpolatory refinable function φ∈H
s
(ℝ) with s>1/2 are Riesz bases of the Sobolev space H
s
(ℝ). This general mixed extension principle also naturally leads to a characterization of the Sobolev norm of a function in
terms of weighted norm of its wavelet coefficient sequence (decomposition sequence) without requiring that dual wavelet frames
should be in L
2(ℝ
d
), which is quite different from other approaches in the literature.
相似文献
11.
Jonatan Lenells 《Arkiv f?r Matematik》2007,45(2):297-325
The topological group of diffeomorphisms of the unit circle of Sobolev class H
k
, for k large enough, is a Banach manifold modeled on the Hilbert space . In this paper we show that the H
1 right-invariant metric obtained by right-translation of the H
1 inner product on defines a smooth Riemannian metric on , and we explicitly construct a compatible smooth affine connection. Once this framework has been established results from
the general theory of affine connections on Banach manifolds can be applied to study the exponential map, geodesic flow, parallel
translation, curvature etc. The diffeomorphism group of the circle provides the natural geometric setting for the Camassa–Holm
equation – a nonlinear wave equation that has attracted much attention in recent years – and in this context it has been remarked
in various papers how to construct a smooth Riemannian structure compatible with the H
1 right-invariant metric. We give a self-contained presentation that can serve as a detailed mathematical foundation for the
future study of geometric aspects of the Camassa–Holm equation. 相似文献
12.
Quillen’s algebraic K-theory is reconstructed via Voevodsky’s algebraic cobordism. More precisely, for a ground field k the algebraic cobordism P1-spectrum MGL of Voevodsky is considered as a commutative P1-ring spectrum. Setting we regard the bigraded theory MGL
p,q
as just a graded theory. There is a unique ring morphism which sends the class [X]MGL of a smooth projective k-variety X to the Euler characteristic of the structure sheaf . Our main result states that there is a canonical grade preserving isomorphism of ring cohomology theories
on the category in the sense of [6], where K*(X
on
Z) is Thomason–Trobaugh K-theory and K′
* is Quillen’s K′-theory. In particular, the left hand side is a ring cohomology theory. Moreover both theories are oriented in the sense of
[6] and ϕ respects the orientations. The result is an algebraic version of a theorem due to Conner and Floyd. That theorem
reconstructs complex K-theory via complex cobordism [1]. 相似文献
13.
Richard Nickl 《Journal of Theoretical Probability》2009,22(1):38-56
Let μ
n
be a sequence of random finite signed measures on the locally compact group G equal to either
or ℝ
d
. We give weak conditions on the sequence μ
n
and on functions K such that the convolution product μ
n
*K, and its derivatives, converge in law, in probability, or almost surely in the Banach spaces
or L
p
(G). Examples for sequences μ
n
covered are the empirical process (possibly arising from dependent data) and also random signed measures
where
is some (nonparametric) estimator for the measure ℙ, including the usual kernel and wavelet based density estimators with
MISE-optimal bandwidths. As a statistical application, we apply the results to study convolutions of density estimators.
相似文献
14.
Semyon Alesker 《Journal of Geometric Analysis》2008,18(3):651-686
A new class of plurisubharmonic functions on the octonionic plane
is introduced. An octonionic version of theorems of A.D. Aleksandrov (Vestnik Leningrad. Univ. Ser. Mat. Meh. Astr. 13(1):5–24,
1958) and Chern-Levine-Nirenberg (Global Analysis, pp. 119–139, 1969), and Błocki (Proc. Am. Math. Soc. 128(12):3595–3599, 2000) are proved. These results are used to construct new examples of continuous translation invariant valuations on convex subsets
of
. In particular, a new example of Spin(9)-invariant valuation on ℝ16 is given.
Partially supported by ISF grant 1369/04. 相似文献
15.
Carlos Castaño-Bernard 《The Ramanujan Journal》2008,17(1):107-121
Certain identities of Ramanujan may be succinctly expressed in terms of the rational function
on the modular curve X
0(N), where
and f
χ
is a certain modular unit on the Nebentypus cover X
χ
(N) introduced by Ogg and Ligozat for prime
and w
N
is the Fricke involution. These correspond to levels N=5,13, where the genus g
N
of X
0(N) is zero. In this paper we study slightly more general kind of relations for each
such that X
0(N) has genus g
N
=1,2, and also for each
such that the Atkin–Lehner quotient X
0+(N) has genus g
N
+=1,2. Finally we study the normal closure of the field of definition of the zeros of the latter.
相似文献
16.
We find all the flat surfaces in the unit 3-sphere $\mathbb{S}^{3}We find all the flat surfaces in the unit 3-sphere
that pass through a given regular curve of
with a prescribed tangent plane distribution along this curve. The formula that solves this problem may be seen as a geometric
analogue of the classical D’Alembert formula that solves the Cauchy problem for the homogeneous wave equation. We also provide
several applications of this geometric D’Alembert formula, including a classification of the flat M?bius strips of
.
相似文献
17.
Soogil Seo 《manuscripta mathematica》2008,127(3):381-396
A circular distribution is a Galois equivariant map ψ from the roots of unity μ
∞ to an algebraic closure of such that ψ satisfies product conditions, for ϵ ∈ μ
∞ and , and congruence conditions for each prime number l and with (l, s) = 1, modulo primes over l for all , where μ
l
and μ
s
denote respectively the sets of lth and sth roots of unity. For such ψ, let be the group generated over by and let be , where U
s
denotes the global units of . We give formulas for the indices and of and inside the circular numbers P
s
and units C
s
of Sinnott over .
This work was supported by the SRC Program of Korea Science and Engineering Foundation (KOSEF) grant funded by the Korea government
(MOST) (No. R11-2007-035-01001-0). This work was supported by the Korea Research Foundation Grant funded by the Korean Government
(MOEHRD, Basic Research Promotion Fund) (KRF-2006-312-C00455). 相似文献
18.
Assume that 1 ≤ p < ∞ and a function f ∈ L p [0, π] has the Fourier series $ \sum\limits_{n = 1}^\infty {a_n } Assume that 1 ≤ p < ∞ and a function f ∈ L
p
[0, π] has the Fourier series cos nx. According to one result of G.H. Hardy, the series cos nx is the Fourier series for a certain function (f) ∈ L
p
[0, π]. But if 1 < p ≤ ∞ and f ∈ L
p
[0, π], then the series cos nx is the Fourier series for a certain function (f) ∈ L
p
[0, π]. Similar assertions are true for sine series. This allows one to define the Hardy operator on L
p
(), 1 ≤ p < ∞, and to define the Bellman operator on L
p
(), 1 < p ≤ ∞. In this paper we prove that the Bellman operator boundedly acts in VMO(), and the Hardy operator also maps a certain subspace C() onto VMO(). We also prove the invariance of certain classes of functions with given majorants of modules of continuity or best approximations
in the spaces H(), L(), VMO() with respect to the Hardy and Bellman operators.
Original Russian Text ? S.S. Volosivets and B.I. Golubov, 2008, published in Izvestiya Vysshikh Uchebnykh Zavedenii. Matematika,
2008, No. 5, pp. 4–13. 相似文献
19.
A. Moutassim 《Advances in Applied Clifford Algebras》2008,18(2):255-267
Résumé. Soit A une algèbre réelle. On suppose que l’espace vectoriel A est muni d’une norme ∥.∥ préhilbertienne vérifiant ∥a
2∥ = ∥a∥2 pour tout . Si A est flexible, sans diviseurs de zéro et de dimension ≤ 4, alors A est isomorphe à ou , ce qui généralise un théorème d’El-Mallah [1]. Si A est flexible, sans diviseurs de zéro, contenant un idempotent central et vérifiant la propriété d’Osborn, alors A est de dimension finie et isomorphe à , ou . Enfin nous montrons qu’une algèbre normée préhilbertienne unitaire d’unité e telle que ∥e∥ = 1 est flexible et vérifie ∥a
2∥ = ∥ a∥2.
Let A be a real algebra. Assuming that a vector space A is endowed with a pre-Hilbert norm ∥.∥ satisfying ∥a 2∥ = ∥a∥2 for all . If A is flexible, without divisor of zero and of a dimension ≤ 4, then A is isomorphic to or , which generalize El-Mallah’s theorem [1]. If A is flexible, without divisor of zero, containing a central idempotent and satisfying Osborn’s properties, then A is finite dimensional and isomorphic to , or . Finally we prove that a normed pre-Hilbert algebra with unit e such that ∥e∥ = 1 is flexible and satisfies ∥a 2∥ = ∥a∥2.
相似文献
20.
Let be open, let be the Dirac operator in and let be the Clifford algebra constructed over the quadratic space . If for fixed, denotes the space of r-vectors in , then an -valued smooth function W = W
r
+ W
r+2 in Ω is said to satisfy the Moisil-Théodoresco system if . In terms of differential forms, this means that the corresponding - valued smooth form w = w
r
+ w
r+2 satisfies in Ω the system d
*
w
r
= 0, dw
r
+ d
*
w
r+2 = 0; dw
r+2 = 0.
Based on techniques and results concerning conjugate harmonic functions in the framework of Clifford analysis, a structure
theorem is proved for the solutions of the Moisil-Théodoresco system.
相似文献