共查询到20条相似文献,搜索用时 31 毫秒
1.
M. Perović 《Commentarii Mathematici Helvetici》1986,61(1):60-66
A homeomorphismf:B
n→B
n of the unit ball inR
n(n≥2) whose coefficient of quasiconformality in the ball of radiusr<1 has asymptotic rate of growthK(r)=sup
|x|≤r
k(x, f)=O(log (1/1−r)) can be continued to a homeomorphism
of the closed ball
. Forn=2 this implies that the Caratheodory theory of prime ends for conformal mappings also holds for the class of homeomorphismsf:B
2→D withK(r)=O(log (1/1−r)).
This work was partially supported by SIZ za nauku SRCG, Titograd. 相似文献
2.
LetS(t) denote a simple random walk inZ
2 with integer timet. The disconnection exponent
is defined by saying the probability that the path ofS starting at 0 and ending at the circle of radiusn disconnects 0 from infinity decays like
. We prove that the disconnection exponent is well-defined and equals the disconnection exponent for Brownian motion which
is known to exist.
Research supported by the National Science Foundation. 相似文献
3.
Yongjin Song 《Israel Journal of Mathematics》1995,90(1-3):189-197
LetR* be a simplicial involutive ring. According to certain involutions onK(R*) and
ε
L
R
∗, there are 1/2-local splittings
and
. It is known [2] that
ε
L
\ga
α
R
∗, the Wall-Witt group. SupposeI→R
S is a split extension of discrete involutive rings withI
2=0, andI is a freeS-bimodule. Then we have
and
. The trace map Tr: Prim
n
∧*M(I ⊗ ℚ)→
0
ρ
n
;I ⊗ ℚ) is an isomorphism. We prove in Lemma 1 that the trace map Tr is ℤ/2-equivariant. In Theorem 2 we show that under a certain
assumption the rational relative Wall-Witt group vanishes. Theorem 2 can be extended to a more general case (Theorem 3) by
employing Goodwillie’s reduction technique [3].
This work was partially supported by KOSEF under Grant 923-0100-010-1. 相似文献
4.
Volker Turau 《Israel Journal of Mathematics》1988,62(2):206-212
For a finite groupG and some prime powerp
n
, the
-subgroup
is defined by
. Meixner proved that ifG is a finite solvable group and
for somen≧1, then the Fitting length of
is bounded by 4n. In the following note it is shown that the 2-length of
is at mostn. This result cannot be derived from Meixner’s paper, since his result implies only that the 2-length is bounded by 2n. 相似文献
5.
Zoé Chatzidakis 《Israel Journal of Mathematics》1986,55(2):173-183
LetK be a hilbertian field,G(K) its absolute Galois group. IfK is countable, then for a.a.
inG(K)
e
,
and there is no intermediate field
with
. Let
∈G(K)
e
. Then for a.a.
in
. 相似文献
6.
Piotr Jakóbczak 《Israel Journal of Mathematics》1990,71(2):145-159
LetF andG be respectively a vector- and a matrix-function in a bounded strictly pseudoconvex domainD, with entries holomorphic inD and continuous in
. We prove that ifF can be divided locally byG with holomorphic factors in a neighborhood of a given pointw inD, and the rank ofG is maximal at all points of
, then the division ofF byG holds globally, with some factors which are holomorphic inD and continuous in
. This method applies also to other function algebras in pseudoconvex domains. 相似文献
7.
Peter Müller 《Israel Journal of Mathematics》1996,94(1):59-91
LetK be a number field, and leth∈K[Y] be a polynomial of degreen. Fix an integer 0≤i≤n and compare the set ν of those integersa ofK such thath(Y)−aY
ihas a root inK with the set
of those integersa, such thath(Y)−aY
iis reducible overK. Ifi is coprime ton, then we classify the rare cases where ν is not cofinite in
. The main tools are a theorem of Siegel about integral points on algebraic curves and the theory of finite groups. 相似文献
8.
LetD be a strictly pseudoconvex domain inC
n
. We prove that
, ϕ a
(0,1)-form, admits solutions inL
p
(∂D), 1≤p<∞ and in BMO, under certain Wolff type conditions of ϕ. Some such results (for 1<p<∞) have previously been obtained by Amar in the ball, but under slightly stronger hypotheses. As a corollary we obtain aH
p
-corona result for two generators.
Partially supported by the Swedish Natural Sciences Research Council. 相似文献
9.
Alexander Prestel 《Israel Journal of Mathematics》1991,73(2):199-205
LetK be an (infinite) number field. IfK is elementarily determined by its absolute Galois groupG(K) (see (1.1) below), thenK is isomorphic to
, R ∩
or some henselian subfield of
. 相似文献
10.
Given ∈, we construct a sequence
, … of Borel sub-sigma-algebras on the unit interval with the following property. Suppose the identity functionf(x)=x is transformed by successive conditioning on
, then
, then
, Then the lim sup, with respect ton, will exceed (pointwise almost-everywhere) 1−∈ and its lim inf will be less than ∈.
The sequence of functions also will fail to converge in the
. This contrasts with the long-open conjecture that if all the
come from a finite set of sigma-algebras, then the resulting sequence of functions must converge in
.
J. L. King was partially supported by NSF grant DMS-9112595. 相似文献
11.
A mapT: X→X on a normed linear space is callednonexpansive if ‖Tx-Ty‖≤‖x-y‖∀x, y∈X. Let (Ω, Σ,P) be a probability space,
an increasing chain of σ-fields spanning Σ,X a Banach space, andT: X→X. A sequence (xn) of strongly
-measurable and stronglyP-integrable functions on Ω taking on values inX is called aT-martingale if
.
LetT: H→H be a nonexpansive mapping on a Hilbert spaceH and let (xn) be aT-martingale taking on values inH. If
then x
n
/n converges a.e.
LetT: X→X be a nonexpansive mapping on ap-uniformly smooth Banach spaceX, 1<p≤2, and let (xn) be aT-martingale (taking on values inX). If
then there exists a continuous linear functionalf∈X
* of norm 1 such that
If, in addition, the spaceX is strictly convex, x
n
/n converges weakly; and if the norm ofX
* is Fréchet differentiable (away from zero), x
n
/n converges strongly.
This work was supported by National Science Foundation Grant MCS-82-02093 相似文献
12.
Lutz Strüngmann 《Israel Journal of Mathematics》2006,151(1):29-51
LetR be a unital associative ring and
two classes of leftR-modules. In [St3] the notion of a (
) pair was introduced. In analogy to classical cotorsion pairs, a pair (V,W) of subclasses
is called a (
) pair if it is maximal with respect to the classes
and the condition Ext
R
1
(V, W)=0 for all
. In this paper we study
pairs whereR = ℤ and
is the class of all torsion-free abelian groups andT is the class of all torsion abelian groups. A complete characterization is obtained assumingV=L. For example, it is shown that every
pair is singly cognerated underV=L.
The author was supported by a DFG grant. 相似文献
13.
Let
be the Heisenberg group and μ
r
be the normalized surface measure on the sphere of radiusr in ℂ
n
. Let
. We prove an optimalL
p-boundedness result for the spherical maximal functionMf, namely we prove thatM is bounded onL
p(I
n
) if and only ifp>2n/2n−1. 相似文献
14.
Isaac Meilijson 《Israel Journal of Mathematics》1973,15(2):193-203
The behavior of (1/N)
asN→∞ is considered, wheref is a bounded measurable function on (−∞, ∞) and (S
n)
n
=1/∞
are the partial sums of a sequence of independent and identically distributed rondom variables. 相似文献
15.
For a smooth functionf on ℝ
n
, we construct an extensionF to ℂ
n
with
vanishing to a high order on ℝ
n
and give precise estimates of how the degree of smothness is reflected in the degree of vanishing. This analysis is used
to define the
operator on (n,n−1) forms with singularities on ℝ
n
. 相似文献
16.
We consider bounded symmetric domains in complex Banach spaces. It is known that each of these domains can be realized as
open unit ballD of a uniquely determined complex Banach spaceE and that every biholomorphic automorphismg ofD extends holomorphically to the closure
ofD inE. We study subsetsS of
(and in particular of the boundary ϖD) such that every automorphismg is already uniquely determined by its values onS. We also consider subsetsS with the analogue topological property: For every sequence (g
n
) of automorphisms converging uniformly onS tog the convergence is already uniform onD.
Supported by Acción Integrada Hispano-Alemana
Supported by Xunta de Galicia, project Xuga 20702 B 90 相似文献
17.
A graphG is embeddable in its complement
ifG is isomorphic with a subgraph of
. A complete characterization is given of those (p,p−1) graphs which are embeddable in their complements. In particular, letG be a (p,p−1) graph wherep≧6 ifp is even andp≧9 ifp is odd; thenG is embeddable in
if and only ifG is neither the starK
1,p−1 norK
1,n
∪C
3 withn≧4. 相似文献
18.
We determine the Zariski-dense subgroups of Chevalley groups and their twisted analogues over infinite algebraic extensions
of finite fields. It turns out that these are essentially forms of the same group (possibly becoming twisted) over smaller
infinite fields. It follows from our classification that if
is a simple algebraic group over the algebraic closure of a finite field, then a dense subgroup of
can never be maximal, and so the maximal subgroups of
are necessarily closed. It follows that Seitz’s determination of the closed maximal subgroups of
actually gives all the maximal subgroups.
It also enables us to prove that ifG is a simple Chevalley group or twisted type over an infinite algebraic extension of a finite field, then in every non-trivial
permutation representation ofG, every finite subgroup has a regular orbit. It follows that every non-trivial permutation module forG over a fieldk iskG-faithful. This is relevant to a programme of studying ideals in group rings of simple locally finite groups.
To John Thompson in recognition of his many outstanding contributions to group theory 相似文献
19.
Lars Hörmander 《Israel Journal of Mathematics》1973,16(1):103-116
Two extensions of a classical theorem of Rellich are proved: (1) LetP=P(−iϖ/ϖx) be a partial differential operator with constant coefficients in
, let the manifolds contained in
have codimension ≧k>0, and denote by Γ an open cone in
intersecting each normal plane of every such manifold. If
,Pu=0 and
it follows thatu=0. (2) Assume in addition that each irreducibe lfactor ofP van shes on a real hypersurface and that Γ contains both normal directions at some such point. If
andP(D) u has compact support, the same condition withk=1 implies thatu has compact support. In both results the hypotheses on the cone Γ and on the operatorP are minimal. 相似文献
20.
Wolfgang Lusky 《Israel Journal of Mathematics》2004,143(1):239-251
LetX be a Banach space with a sequence of linear, bounded finite rank operatorsR
n:X→X such thatR
nRm=Rmin(n,m) ifn≠m and lim
n→∞
R
n
x=x for allx∈X. We prove that, ifR
n−Rn
−1 factors uniformly through somel
p and satisfies a certain additional symmetry condition, thenX has an unconditional basis. As an application, we study conditions on Λ ⊂ ℤ such thatL
Λ=closed span
, where
, has an unconditional basis. Examples include the Hardy space
. 相似文献