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1.
We prove that, in a locally -solvable group G = AB with locally normal subgroups A and B, there exist pairwise-permutable Sylow - and p-subgroups A
, A
p
and B
, B
p
, p , of the subgroups A and B, respectively, such that A
B
is a Sylow -subgroup of the group G and, for an arbitrary nonempty set
,
are Sylow - and -subgroups, respectively, of the group G. 相似文献
2.
A. I. Il'inskii 《Mathematical Notes》1977,21(5):400-405
In the framework of the theory of D. Kendall's delphic semigroups are considered problems of divisibility in the semigroup of convex characteristic functions on the semiaxis (0,). Letn ()={:1¦11 or 1=}, and Io()={: 1¦ 1 N()}. The following results are proved: 1) The semigroup is almost delphic in the sense of R. Davidson. 2) N() is a set of the type G which is dense in (in the topology of uniform convergence on compacta). 3) The class Io() contains only the function identically equal to one.Translated from Matematicheskie Zametki, Vol. 21, No. 5, pp. 717–725, May, 1977.The author thanks I. V. Ostrovskii for the formulation of the problem and valuable remarks. 相似文献
3.
A. K. Guts 《Mathematical Notes》1973,13(5):411-415
Let n be n-dimensional Lobachevskii space, and {lx:x n} be a family of lines, parallel to a linel
0, 0n (in a given direction). Let {cx:Xn} be a family of circular cones in n of opening with axes lX and vertex X. Then, iff:nn(n>2) is a bijective mapping andf(Cx)=C
f(x), it follows thatf is a motion in the space n.Translated from Matematicheskie Zametki, Vol. 13, No. 5, pp. 687–694, May, 1973. 相似文献
4.
Summary Let be thek-dimensional subspace spanned by the translates (·–2j/k),j=0, 1, ...,k–1, of a continuous, piecewise smooth, complexvalued, 2-periodic function . For a given functionfL
2(–, ), its least squares approximantS
kf from can be expressed in terms of an orthonormal basis. Iff is continuous,S
kf can be computed via its discrete analogue by fast Fourier transform. The discrete least squares approximant is used to approximate Fourier coefficients, and this complements the works of Gautschi on attenuation factors. Examples of include the space of trigonometric polynomials where is the de la Valleé Poussin kernel, algebraic polynomial splines where is the periodic B-spline, and trigonometric polynomial splines where is the trigonometric B-spline. 相似文献
5.
H. R. Friedlein 《Journal of Geometry》1981,16(1):103-116
Let the following motions in a projective elliptic space(K,) be called normal forms:Subspace-reflections, rotations, the product of a rotation and a point-reflection whose center lies on the axis of the rotation and the product of two rotations, whose axes of rotation are conjugated.It is shown that all motions of(K, ) have a normal-form provided any two lines of(K, ) have a common perpendicular. The latter is true if and only if K is Pythagorean and if the polarity can be represented by the unit-matrix. 相似文献
6.
Frieder Knüppel 《Journal of Geometry》1987,29(2):170-181
A generalized projective plane is an incidence structure together with a relation distant on the set of points and also on the set of lines, such that any two distant points A,B (lines a,b) have a unique common line (A,B) (common point (a,b)) and three further axioms hold. Every commutative ring with 1 supplies a model. A homomorphism of into an incidence structure
is called regular if the following condition and its dual are valid: A distant B and c IA,B implies c=(A,B). We shall prove the following two theorems. Let be a generalized projective plane satisfying a richness condition called (U). Let M I m. If and are regular homomorphisms of such that X = M X = M for each point X of the line m then A = B A = B for any two points A,B. If is a projective plane over a commutative ring such that (U) holds then the surjective regular homomorphisms of are induced by the ideals of the ring; in particular, the image of under a regular homomorphism is again a projective plane over a ring, and preserves distant. 相似文献
7.
Kurt Retter 《manuscripta mathematica》1981,34(2-3):279-291
Let XS be a holomorphic map, and let RX×SX be an equivalence relation. The restriction of R to the fibre –1(S) is denoted by Rs. The quotient X/R is called a relative complex quotient, if the quotient map XX/R is holomorphic over S. Two cases are studied: (C) All fibres of are locally Rs-separable (relative Cartan quotient); (R) All fibres of are holomorphically convex, and Rs is given by tke holomorphic functions on –1 (s) (relative Remmert quotient). 相似文献
8.
K. I. Oskolkov 《Mathematical Notes》1970,8(1):496-503
Necessary and sufficient conditions are derived for the convergence of a trigonometric series to a function of bounded variation on the interval (, ) [-, ]. For the case in which the coefficients satisfy certain conditions, the continuity of the sum function is investigated.Translated from Matematicheskie Zametki, Vol. 8, No. 1, pp. 47–58, July, 1970.The author wishes to thank his scientific supervisor S. A. Telyakovskii for suggesting this problem and for his interest in the work. 相似文献
9.
Let M be a compact manifold and A a finite subgroup of the outer automorphism group Out 1(M) of 1(M). A necessary condition for realising A by an isomorphic group of homeomorphisms of M is the existence of an extension to the abstract kernel (A, 1(M), : AOut 1(M)). If the center of 1(M) is nontrivial this condition need not be fulfilled. We show however, that we can find a finite group B with a normal abelian subgroup C with B/CA, and such that there exists an extension to the abstract kernel (B, 1(M), : BAOut 1(M)). In the case of Seifert fiber spaces or flat Riemannian manifolds B can be ralized by an isomorphic group of homeomorphisms of M. 相似文献
10.
In this paper we study the degree of approximation of functionsf inC
2 andC
2
1
by the operatorsV
n ofde la Vallée Poussin. The quality of approximation is measured in terms of the modulus of continuity off andf respectively. Forn so-called exact constants of approximation are determined. Furthermore, the asymptotic behaviour of these constants is investigated asn. 相似文献
11.
H. Scheerer 《manuscripta mathematica》1985,51(1-3):63-87
Let R be a subring of the rationals with 1/2, 1/3R; let S
R
n
denote the R-local n-sphere and define
R
n
:=S
R
n
for n odd,
R
n
:=S
R
n
for n>0 even. An H-space (resp. a 1-conn. co-H-space) is decomposable over R, if it is homotopy equivalent to a weak product of spaces
R
n
(resp. to a wedge of R-local spheres). We prove that, if E is grouplike decomposable of finite type over R, the functor [-,E] is determined on finite dim. complexes by the Hopf algebra M*(E;R); here M* denotes the unstable cohomotopy functor of H.J. Baues. If C is cogrouplike decomposable over R, the functor [C,-] is determined on 1-conn. R-local spaces by *(C) as a cogroup in the category of M-Lie algebras. For R = the functor [-,E] is also determined by the Lie algebra *(E) and [C,-] by the Berstein coalgebra associated to the comultiplication of C. 相似文献
12.
Gunnar Englund 《Probability Theory and Related Fields》1982,60(3):381-391
Summary Each element in a finite population is assigned a bonus value, i.e. a real number. Elements are selected from by simple random sampling with replacement and with equal draw probabilities. Each time we receive a new element, i.e. an element which has not been previously selected, we receive the corresponding bonus. Let W
n denote the bonus sum after n selections. It is well known that W
n is approximately normally distributed under mild conditions. We give a remainder term estimate of the Berry-Esseen type for this normal distribution approximation. 相似文献
13.
A. N. Bakhvalov 《Analysis Mathematica》2001,27(1):3-36
Let a ={nlna (n+1)}, where a R. The following results are established: For every &fnof a BV ((- ]2), the triangular partial sums of its Fourier series are uniformly bounded if a = -1, and converge everywhere if a < -1.For every a>0, there exists &fnof a BV ((- ]2) such that the triangular partial sums of its Fourier series are unbounded at the point (0;0). 相似文献
14.
Todd Kapitula Stanislaus Maier-Paape 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1996,47(2):265-305
We consider the dynamics of the Ginzburg-Landau equation in a small neighborhood of a known pulse solution by studying a Poincaré map,P:
T
T
, where
T
is a section which is transverse to the pulse. Due to the fact that the Ginzburg-Landau equation possesses both a rotational symmetry and a spatial symmetry, we are able to conduct a detailed analytical study of this map in neighborhoods arbitrarily close to the pulse solution. Thus, we are able to complement the work of Holmes [8], who conducted an analytical study of the Poincaré map in a punctured neighborhood of the pulse. We find that the Poincaré map contains an invariant set itT, where is not necessarily a Cantor set of points, such thatP: is homeomorphic to a shift map on (at least) two symbols. Furthermore, we find that for eachm 1 the mapP
itm possesses a fixed point. Since is not necessarily a Cantor set, this is not immediately clear. Finally, we find that when the pulse solution is broken, for eachm1 there exist parameter values such that pulses possessingm maxima appear.On leave at the University of Utah during 1993/94. Supported by the DFG, Habilitationsstipendium Ma 1587/1-1. 相似文献
15.
This paper investigates the properties of (0) optimal policies in the model of [2]. It is shown that, if * = (
0
*
,
1
*
,...,
n
*
,
n
+1/*
, ...) is a-discounted optimal policy, then (
0
*
,
1
*
, ...,
n
*
) for alln0 is also a-discounted optimal policy. Under some condition we prove that stochastic stationary policy
n
*
corresponding to the decision rule
n
*
is also optimal for the same discounting factor. We have also shown that for each-optimal stochastic stationary policy
0
*
,
0
*
can be decomposed into several decision rules to which the corresponding stationary policies are also-optimal separately; and conversely, a proper convex combination of these decision rules is identified with the former
0
*
. We have further proved that for any (,)-optimal policy, say *=(
0
*
,
1
*
, ...,
n
*
,
n
+1/*
, ...),
n–1
*
) is ((1–
n
)–1
e, ) optimal forn>0. At the end of this paper we mention that the results about convex combinations and decompositions of optimal policies of § 4 in [1] can be extended to our case.Project supported by the Science Fund of the Chinese Academy of Sciences. 相似文献
16.
Chihiro Suetake 《Geometriae Dedicata》1994,51(2):123-131
Let be a translation plane of orderq
3,q an odd prime power, whose kern GF(q). Letl
be the line at infinity of . LetG be a solvable collineation group of in the linear translation complement, which acts transitively onl
, and letH be a maximal normal cyclic subgroup ofG. Then the restriction
ofH onl
acts semiregularly onl
and
{1, 2, 3, 6}, where
is the restriction ofG onl
(ifq –1(mod 3), then
{1, 2}). Ifq {3, 5} and
{1, 2}, then is determined completely, using a computer. 相似文献
17.
Michael Kapovich 《Inventiones Mathematicae》1995,119(1):243-265
Summary We prove that for any nonelementary representation : 1(S SL (2, )) of the fundamental group of a closed orientable hyperbolic surfaceS there exists a complex projective structure onS with the monodromy .Oblatum IV-1993 & 24-IV-1994 相似文献
18.
We find conditions under which the ratio of particle and antiparticle total scattering cross sections as s. If the forward elastic scattering amplitudes become purely real asymptotically, then their ratio tends to –1. We prove that /–(s)1 for +(s)/m
2, where m
is the -meson mass. We show that the asymptotic relations obtained have finite-energy analogues for some processes. 相似文献
19.
Masahiro Ohno 《Geometriae Dedicata》1992,44(3):335-347
Let : X Y be a morphism of smooth projective varieties over an algebraically closed field k of characteristic not equal to 2 whose closed fibres are all isomorphic to
r
P1 and let ': X
r
P1 be a surjective morphism. This article gives a sufficient condition concerning ' and Y under which X is isomorphic to Y×
r
P1. 相似文献
20.
We prove the Jackson theorem for a zero-preserving approximation of periodic functions (i.e., in the case where the approximating polynomial has the same zeros y
i) and for a sign-preserving approximation [i.e., in the case where the approximating polynomial is of the same sign as a function f on each interval (y
i, y
i – 1)]. Here, y
i are the points obtained from the initial points – y
2s
y
2s–1 <...< y1 < using the equality yi = yi + 2s + 2 furthermore, these points are zeros of a 2-periodic continuous function f. 相似文献