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1.
L. M. Slepova 《Mathematical Notes》1977,21(6):485-486
A formation
is called radical (weakly n-radical) if it contains every group G which can be represented in the formG=M
1M2 ...M
n,M
iG, where the subgroups Mi belong to
(belong to
and have pairwise prime indices). It is proved that a local formation
is radical (weakly n-radical,n 2) if and only if its complete inner local screen f has the following property: f(p) is a radical (a weakly n-radical,n 2) formation for every prime number p.Translated from Matematicheskie Zametki, Vol. 21, No. 6, pp. 861–864, June, 1977. 相似文献
2.
LetS be a 0-distributive semilattice and
be its minimal spectrum. It is shown that
is Hausdorff. The compactness of
has been characterized in several ways. A representation theorem (like Stone's theorem for Boolean algebras) for disjunctive, 0-distributive semilattices is obtained. 相似文献
3.
4.
Jürgen Franke 《Probability Theory and Related Fields》1985,68(3):337-364
Summary We discuss a robust approach for predicting a weakly stationary discrete time series whose spectral density f is not exactly known. We assume that we know that f
), where
is a convex set of spectral densities fulfilling some not too stringent conditions. We proof the existence of a most indeterministic density f
0 in
, and we show that the classical optimal linear predictor for a time series with spectral density f
0 is mini-max-robust in the sense that it minimizes the maximal possible prediction error.We investigate some special models
, and, in doing so, we illustrate a generally applicable method for determining the robust predictor. In particular, we discuss model sets
which are defined by conditions on a finite part of the autocovariance sequence of the corresponding time series. These examples are of particular interest as the most indeterministic density is an autoregressive one, i.e. the robust predictor is finite. We discuss connections between this type of model set
and maximum entropy and generalized maximum entropy spectral estimates. 相似文献
5.
M. Emery 《Probability Theory and Related Fields》1980,51(1):95-100
Summary Let (,
, P) be a complete probability space; let
t0 be an increasing right-continuous family of
-complete sub--fields of
; let
be a sequence of semimartingales. Assume that for all positive t and for all bounded predictable processes H, the r.v.'s
converge in probability to a limit J(t, H) when n tends to infinity. Then there exists a semimartingale X such that, for all t and H, J(t, H)=
. 相似文献
6.
Ralph McKenzie 《Algebra Universalis》1984,18(1):29-69
A construction is defined which associates, to every algebra
of a fixed but arbitrary finite similarity type, a groupoidF
. The identities ofF
are finitely based if and only if those of
are, andF
is finite if and only if
is finite. Up to isomorphism,F
has the same endomorphism monoid and subalgebra lattice as
, but the congruence lattice ofF
is the result of adjoining a new 1 to the congruence lattice of
.F is functorial, preserves the satisfaction (and the non-satisfaction) of most Mal'cev conditions, and produces, by composition with the operation of forming the generated variety, an isomorphism of the lattice of varieties of fixed type to an interval in the lattice of varieties of groupoids.The construction makes use of a new product operation, applicable to two algebras of differing similarity types, which is introduced and studied in this paper.Research supported by National Science Foundation grant MCS-8103455.Presented by K. A. Baker. 相似文献
7.
Let x(w), w=u+iv B, be a minimal surface in 3 which is bounded by a configuration , S consisting of an arc and of a surface S with boundary. Suppose also that x(w) is area minimizing with respect to , S. Under appropriate regularity assumptions on and S, we can prove that the first derivatives of x(u, v) are Hölder continuous with the exponent =1/2 up to the free part of B which is mapped by x(w) into S. An example shows that this regularity result is optimal. 相似文献
8.
S. N. Chernikov 《Mathematical Notes》1968,4(1):543-545
It is proved that if a periodic group
has an extremal normal divisor
, determining a complete abelian factor group
, then the center of the group
contains a complete abelian subgroup
, satisfying the relation
and intersecting
on a finite subgroup. It is also established with the aid of this proposition that every periodic group of automorphisms of an extremal group
is a finite extension of a contained in it subgroup of inner automorphisms of the group
.Translated from Matematicheskie Zametki, Vol. 4, No. 1, pp. 91–96, July, 1968. 相似文献
9.
Yu. L. Shmul'yan 《Mathematical Notes》1976,20(4):843-848
Let
be a connected, finite-dimensional, complex analytic manifold; let T() be an analytic function defined on
, whose values are J-biexpanding operators on a J-space H. Let
(A) denote the range of A. The following assertions are proved: 1. The lineals
and
do not depend on . 2. For arbitrary
we have
Translated from Matematicheskie Zametki, Vol. 20, No. 4, pp. 511–520, October, 1976. 相似文献
10.
Let G be an arbitrary FC-group, let R be its locally soluble radical, and let L/R = L(G/R). We prove that, for N G, G/N is residually finite if R
N
L. 相似文献
11.
Dr. Detlev Poguntke 《Monatshefte für Mathematik》1976,82(1):31-50
This is a continuation of the paper Zwei Klassen lokalkompakter maximal fastperiodischer Gruppen, [6]. In [6], the classes
and
were introduced. We give sufficient conditions to conclude thatG is in
if one knows thatG/G
0 is in
. If a groupG is in
and ifG satisfies the Chu-duality then all closed subgroups ofG satisfy the Chu-duality. The Chu-quasi-dual of the Heisenberg groupH with integral coefficients is computed. It is shown thatH does not satisfy the Chu-duality, thatH is in
, and thatH is not in
. 相似文献
12.
Michel Duflo 《Inventiones Mathematicae》1982,67(3):385-393
Résumé Soient
une algèbre de Lie de dimension finie et
une sousalgèbre de Lie de
. Je montre que l'induction, qui envoie les idéaux de l'algèbre enveloppante de
dans les idéaux de l'algèbre enveloppante de
, commute, à une torsion près, à l'anti-automorphisme principal. La résolution libre standard de la représentation triviale d'une algèbre de Lie joue un rôle important dans la démonstration.
Convention. On fixe un corps commutatifk. Tous les espaces vectoriels, produits tensoriels et algèbres considérés dans cet article sont surk.
Notations. Si g est une algèbre de Lie, on noteU(g) son algèbre enveloppante. On noteu l'anti-automorphisme principal deU(g): c'est l'antiautomorphisme tel que pourXg. Si est une forme linéaire sur g, nulle sur [g,g], on noteuu
l'automorphisme deU(g) tel queX
=X+(X) pourXg. Si g est de dimension finie, la fonction module de g est la forme linéaireXtradX. 相似文献
Summary Let be a finite dimensional Lie algebra, and a Lie subalgebra. I show that the induction map, between the sets of ideals in the enveloping algebras of and , commutes, up to a twisting, with the principal anti-automorphism. The standard free resolution of the trivial representation of a Lie algebra plays an important role in the proof.
Convention. On fixe un corps commutatifk. Tous les espaces vectoriels, produits tensoriels et algèbres considérés dans cet article sont surk.
Notations. Si g est une algèbre de Lie, on noteU(g) son algèbre enveloppante. On noteu l'anti-automorphisme principal deU(g): c'est l'antiautomorphisme tel que
13.
Yuri I. Karlovich Enrique Ramírez de Arellano 《Integral Equations and Operator Theory》2001,39(4):441-474
LetB be the Banach algebra of all bounded linear operators on the weighted Lebesgue spaceL
p (T, ) with an arbitrary Muckenhoupt weight on the unit circleT, and
the Banach subalgebra ofB generated by the operators of multiplication by piecewise continuous coefficients and the operatorse
h,S
T
e
h,
–1
I (hR, T) whereS
T is the Cauchy singular integral operator ande
h,(t)=exp(h(t+)/(t–)),tT. The paper is devoted to a symbol calculus, Fredholm criteria and an index formula for the operators in the algebra
and its matrix analogue
. These shift-invariant algebras arise naturally in studying the algebras of singular integral operators with coefficients admitting semi-almost periodic discontinuities and shifts being diffeomorphisms ofT onto itself with second Taylor derivatives.Partially supported by CONACYT grant, Cátedra Patrimonial, No. 990017-EX and by CONACYT project 32726-E, México. 相似文献
14.
Let
be a reductive Lie algebra over C. We say that a
-module M is a generalized Harish-Chandra module if, for some subalgebra
, M is locally
-finite and has finite
-multiplicities. We believe that the problem of classifying all irreducible generalized Harish-Chandra modules could be tractable. In this paper, we review the recent success with the case when
is a Cartan subalgebra. We also review the recent determination of which reductive in
subalgebras
are essential to a classification. Finally, we present in detail the emerging picture for the case when
is a principal 3-dimensional subalgebra. 相似文献
15.
In this paper, Ore extensions in the class of Hopf algebras are studied. The classification theorem enables one to describe the Hopf--Ore extensions for the group algebras, for the algebras
and
, and for the quantum ax + b group. 相似文献
16.
Hermann Hähl 《Geometriae Dedicata》1990,36(2-3):181-197
New results of Salzmann and Hubig say that a 16-dimensional (locally) compact topological projective plane in which the group
of continuous collineations has dimension 40 is a translation plane. It is therefore important to determine all 16-dimensional locally compact translation planes with dim
40. From previous work of the author ([10]), it is known that such a plane is either the classical octonion plane, or dim
=40 and
contains a subgroup isomorphic to the compact exceptional group G2, but no larger compact simple subgroup. In the present paper, all planes satisfying the latter property more generally with dim
38 are explicitly determined. Together with the classification of all 16-dimensional locally compact translation planes in which
contains Spin(7) given by the author in [8], one thus knows all 16-dimensional locally compact translation planes with
containing G2 and dim
38. Via suitable Baer subplanes, the classification makes use of analogous results for 8-dimensional planes ([7]).
Meinem verehrten Lehrer Helmut Salzmann zum 60. Geburtstag 相似文献
Meinem verehrten Lehrer Helmut Salzmann zum 60. Geburtstag 相似文献
17.
Prof. Dr. E. Binz 《Monatshefte für Mathematik》1980,89(4):275-288
OnE(M,
n
), the Fréchet-manifold of all smooth embeddings of a smooth, compact, closed, orientable manifoldM (of dimensionn-1) into
n
two natural metricsG and
are considered. The metric
plays a central rôle in elasticity theory. Using a generalised notion of the Fréchet derivative their respective spraysS and
and the correspoonding Levi-Civita connections are computed. BothS and
are smooth in a well defined sense. In contrast toS the spray
turns out to be trivial. 相似文献
18.
Alain Escassut 《Annali di Matematica Pura ed Applicata》1987,147(1):73-92
Summary Let K be a complete ultrametric algebraically closed field. Let D be a bounded closed strongly infraconnected set in K with no T-filter, and let H(D) be the Banach algebra of the analytic elements in D. Let r, r be functions from D toR with bounds a, b such that 0
(D,r,r) be the Banach algebra of the Laurent series with coefficients as in H(D) such that
, provided with a suitable norm. In
(D, r, r) we give a kind of Hensel Factorization for series whose dominating coefficients at r(x) and at r(x) conserve the same rank. We take advantage of this method to correcting a mistake that happened in our previous article on the Hensel Factorization for Taylor series.And Erratum to «Maximum principle for analytic elements and Lubin-Hensel's Theorem inH(D)Y»,135, pp. 265–278 of this Journal. 相似文献
19.
For 1/p+1/q1, we study the closed ideal
formed by the (c
o
,p,q)-summing operators. It turns out thatT:XY does not belong to
if and only if it factors the mapId:l
p
*l
q
. By localization, we get the ideal
that consists of those operatorsT for which all ultrapowersT
u
are contained in
. Operators in the complement of
are characterized by the property that they factor the mapsId:l
p
*n
l
q
n
uniformly. Our main tools are ideal norms.Supported by DFG grant PI 322/1-2 相似文献
20.
Anna Maria Candela 《Annali di Matematica Pura ed Applicata》1996,171(1):131-158
Let ., z
be a Lorentz metric on a manifold
such that
isnot compact. We prove the existence of infinitely many lightlike periodic trajectories in
by using variational methods and Ljusternik-Schnirelman theory.Sponsored by M.U.R.S.T. (fondi 60% «Problemi differenziali nonlineari e teoria dei punti critici»; fondi 40% «Equazioni differenziali e calcolo delle variazioni»). 相似文献