共查询到20条相似文献,搜索用时 31 毫秒
1.
Jérémy Blanc 《manuscripta mathematica》2006,119(2):225-241
We describe the conjugacy classes of affine automorphisms in the group Aut(n,) (respectively Bir()) of automorphisms (respectively of birational maps) of . From this we deduce also the classification of conjugacy classes of automorphisms of ℙn in the Cremona group Bir(). 相似文献
2.
Amílcar Pacheco 《manuscripta mathematica》2005,118(3):361-381
Let be a smooth projective curve defined over a number field k, A/k() an abelian variety and (τ, B) the k()/k-trace of A. We estimate how the rank of A(k())/τB(k) varies when we take a finite geometrically abelian cover defined over k.
This work was partially supported by CNPq research grant 304424/2003-0, Pronex 41.96.0830.00 and CNPq Edital Universal 470099/2003-8.
I would like to thank Douglas Ulmer for comments on how to treat the case of arbitrary ramification, but the conductor prime
to the ramification locus, in the case of elliptic fibrations. I would also like to thank Marc Hindry for comments on the
inequality comparing the conductors of A and A'. Finally, I also thank the referee for his comments and criticisms. 相似文献
3.
Tom Weston 《manuscripta mathematica》2005,118(2):161-180
Fix a residual ordinary representation :GF→GLn(k) of the absolute Galois group of a number field F. Generalizing work of Greenberg–Vatsal and Emerton–Pollack–Weston, we show that the Iwasawa invariants of Selmer groups of
deformations of depends only on and the ramification of the deformation. 相似文献
4.
Shu-Yu Hsu 《Mathematische Annalen》2006,334(1):153-197
Let a1,a2, . . . ,am ∈ ℝ2, 2≤f ∈ C([0,∞)), gi ∈ C([0,∞)) be such that 0≤gi(t)≤2 on [0,∞) ∀i=1, . . . ,m. For any p>1, we prove the existence and uniqueness of solutions of the equation ut=Δ(logu), u>0, in satisfying and logu(x,t)/log|x|→−f(t) as |x|→∞, logu(x,t)/log|x−ai|→−gi(t) as |x−ai|→0, uniformly on every compact subset of (0,T) for any i=1, . . . ,m under a mild assumption on u0 where We also obtain similar existence and uniqueness of solutions of the above equation in bounded smooth convex domains of ℝ2 with prescribed singularities at a finite number of points in the domain. 相似文献
5.
6.
The aim of this note is to understand under which conditions invertible modules over a commutative -algebra in the sense of Elmendorf, Kriz, Mandell & May give rise to elements in the algebraic Picard group of invertible graded modules over the coefficient ring by taking homotopy groups. If a connective commutative -algebra R has coherent localizations for every maximal ideal , then for every invertible R-module U, U*=π*U is an invertible graded R*-module. In some non-connective cases we can carry the result over under the additional assumption that the commutative -algebra has ‘residue fields’ for all maximal ideals if the global dimension of R* is small or if R is 2-periodic with underlying Noetherian complete local regular ring R0. We apply these results to finite abelian Galois extensions of Lubin-Tate spectra. 相似文献
7.
Sven Winklmann 《manuscripta mathematica》2005,118(4):485-499
We consider immersed hypersurfaces :Mn→ℝn+1 with prescribed anisotropic mean curvature . Such hypersurfaces can be characterized as critical points of parametric functionals of the type with an elliptic Lagrangian F depending on normal directions and a smooth vectorfield Q satisfying . We establish curvature estimates for stable hypersurfaces of dimension n≤5, provided F is C3-close to the area integrand. 相似文献
8.
Yu Zhang 《Probability Theory and Related Fields》2006,136(2):298-320
We consider the first passage percolation model on Z
d
for d ≥ 2. In this model, we assign independently to each edge the value zero with probability p and the value one with probability 1−p. We denote by T(0, ν) the passage time from the origin to ν for ν ∈ R
d
and
It is well known that if p < p
c
, there exists a compact shape B
d
⊂ R
d
such that for all
> 0,
t
B
d
(1 −
) ⊂ B(t) ⊂ tB
d
(1 +
) and G(t)(1 −
) ⊂ B(t) ⊂ G(t)(1 +
) eventually w.p.1. We denote the fluctuations of B(t) from tB
d
and G(t) by
In this paper, we show that for all d ≥ 2 with a high probability, the fluctuations F(B(t), G(t)) and F(B(t), tB
d
) diverge with a rate of at least C log t for some constant C. The proof of this argument depends on the linearity between the number of pivotal edges of all minimizing paths and the
paths themselves. This linearity is also independently interesting.
Research supported by NSF grant DMS-0405150 相似文献
9.
Attila Wiebe 《manuscripta mathematica》2006,120(1):27-38
Let R be a positive normal affine semigroup ring of dimension d and let be the maximal homogeneous ideal of R. We show that the integral closure of is equal to for all n ∈ℕ with n ≥ d − 2. From this we derive that the Rees algebra R[t] is normal in case that d ≤ 3. If emb dim(R) = d + 1, we can give a necessary and sufficient condition for R[t] to be normal. 相似文献
10.
The aim of this paper is to obtain necessary and sufficient conditions for uniform exponential trichotomy of evolution families
on the real line. We prove that if p ∈ (1,∞) and the pair (Cb(R,X),Cc(R,X)) is uniformly p-admissible for an evolution family ={U(t,s)}t≥s then is uniformly exponentially trichotomic. After that we analyze when the uniform p-admissibility of the pair (Cb(R, X), Cc(R, X)) becomes a necessary condition for uniform exponential trichotomy. As applications of these results we study the uniform
exponential dichotomy of evolution families. We obtain that in certain conditions, the admissibility of the pair (Cb(R,X),Lp(R,X)) for an evolution family ={U(t,s)}t≥s is equivalent with its uniform exponential dichotomy. 相似文献
11.
In this work, we determine all modular curves X1(M,N) which are bielliptic, and then we also discuss the problem of finding the curves X1(M,N) which admit infinitely many quartic points over . 相似文献
12.
Let X={Xt,t≥0} be a symmetric Markov process in a state space E and D an open set of E. Let S(n)={S(n)t, t ≥ 0} be a subordinator with Laplace exponent ϕn and S={St,t≥0} a subordinator with Laplace exponent ϕ. Suppose that X is independent of S and S(n). In this paper we consider the subordinate processes and and their subprocesses and Xϕ,D killed upon leaving D. Suppose that the spectra of the semigroups of and Xϕ,D are all discrete, with being the eigenvalues of the generator of and being the eigenvalues of the generator of Xϕ,D. We show that, if limn→∞ϕn(λ)=ϕ(λ) for every λ>0, then
The research of this author is supported in part by NSF Grant DMS-0303310.
The research of this author is supported in part by a joint US-Croatia grant INT 0302167. 相似文献
13.
Árpád Tóth 《manuscripta mathematica》2005,116(3):277-295
For a simple Chevalley group G an explicit version of the Solomon-Tits theorem is proved by describing the generators of the kernel of the map Z[G(K)]SK, where K is any field and where SK is the Steinberg module of the group G(K). As a corollary it is shown that if is a Euclidean domain whose fraction field is K, then SK is cyclic as a G() module when G is either a classical group or an exceptional group of type E6, or E7.Acknowledgement I would like to thank Matt Emerton, Özlem Imamoglu, Paul Gunnells for several helpful comments. 相似文献
14.
Hideyo Sasaki 《manuscripta mathematica》2006,119(1):97-106
Let be a real quadratic field with m a square-free positive rational integer, and be the ring of integers in F. An -lattice L on a totally positive definite quadratic space V over F is called r-universal if L represents all totally positive definite -lattices l with rank r over . We prove that there exists no 2-universal -lattice over F with rank less than 6, and there exists a 2-universal -lattice over F with rank 6 if and only if m=2, 5. Moreover there exists only one 2-universal -lattice with rank 6, up to isometry, over . 相似文献
15.
In this paper, we provide a suitable theory for the energy
where μ is a Radon measure and Γ is the fundamental solution of a sub-Laplacian on a stratified group As a significant application, we prove the quasi-continuity of superharmonic functions related to . The proofs are elementary and mostly rely on the use of appropriate mean-value formulas and mean-integral operators relevant
to the Potential Theory for . 相似文献
16.
In lectures given in 1953 at New York University, Franz Rellich proved that for all f∈C0∞(Rn \{0}) and n≠2where the constant C(n):=n2(n−4)2/16 is sharp. For n=2 extra conditions were required for f, and for n=4, C(4)=0, producing a trivial inequality. Influenced by recent work of Laptev-Weidl on Hardy-type inequalities in R2, the authors show that for n≥2, the inclusion of a magnetic field B=curl(A) of Aharonov-Bohm type yields non-trivial Rellich-type inequalities of the formwhere ΔA=(∇−iA)2 is the magnetic Laplacian. As in the Laptev-Weidl inequality, the constant C(n,α) depends upon the distance of the magnetic flux to the integers Z. When the flux is an integer and α=0, the inequalities reduce to Rellich’s inequality.The first author gratefully acknowledges the hospitality and support of the Mathematics Department at UAB where much of this work was done. 相似文献
17.
Let D be a domain, E a subset of its quotient field K, and Int. The polynomial closure of E is the set We compare the polynomial closure with the divisorial closure in a general setting and then in an essential domain. Especially, we show that these two closures of ideals are the same if D is a Krull-type domain.This work was done while the first author was visiting KIAS. She would like to thank KIAS for the hospitality and support. 相似文献
18.
We describe the possible restrictions of the cotangent bundle to an elliptic curve . We apply this in positive characteristic to the computation of the Hilbert-Kunz function of a homogeneous R+-primary ideal in the graded section ring . 相似文献
19.
We study numerical integration for functions f with singularities. Nonadaptive methods are inefficient in this case, and we show that the problem can be efficiently solved by adaptive quadratures at cost similar to that for functions with no singularities.
Consider first a class of functions whose derivatives of order up to r are continuous and uniformly bounded for any but one singular point. We propose adaptive quadratures Q*n, each using at most n function values, whose worst case errors are proportional to n−r. On the other hand, the worst case error of nonadaptive methods does not converge faster than n−1.
These worst case results do not extend to the case of functions with two or more singularities; however, adaption shows its
power even for such functions in the asymptotic setting. That is, let F∞r be the class of r-smooth functions with arbitrary (but finite) number of singularities. Then a generalization of Q*n yields adaptive quadratures Q**n such that |I(f)−Q**n(f)|=O(n−r) for any f ∈ F∞r. In addition, we show that for any sequence of nonadaptive methods there are `many' functions in F∞r for which the errors converge no faster than n−1.
Results of numerical experiments are also presented.
The authors were partially supported, respectively, by the State Committee for Scientific Research of Poland under Project
1 P03A 03928 and by the National Science Foundation under Grant CCR-0095709. 相似文献
20.
Valentin Savin 《manuscripta mathematica》2006,119(3):287-303
Let = [X/G] be the quotient stack of a scheme X by an affine group scheme G over a field k. Assume that there is a line bundle on whose underlying line bundle on X is very ample. Let VB() be the category of vector bundles on .We show that is canonically isomorphic to the stack of fiber functors on VB(). This is an analogue of the Tannaka duality for affine groups.
Partially supported by CNCSIS contract no. 33079/2004 相似文献