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1.
Factorizations of One-Generated Composition Formations 总被引:2,自引:0,他引:2
A non-empty formation
of finite groups is said to be solubly saturated, or we call it a composition formation, if every finite group G having a normal subgroup N such that
belongs to
. An intersection of all composition formations containing a given group G is denoted cformG. Conditions are described under which
has the form
, where
. 相似文献
2.
R. S. Davtyan 《Mathematical Notes》1969,6(4):725-732
It is shown that for convergence of every orthonormal system
n(x) given on [0, l],it is necessary and sufficient that, under the condition
on tlie increasing function W(x) and for
there hold
almost everywhere on [0, 1].Translated from Matematicheskie Zametki, Vol. 6, No. 4, pp. 451–462, October, 1969. 相似文献
3.
Conditions are found upon satisfaction of which the differential equation
相似文献
4.
The purpose of this paper is to present the solution of time-optimal problem ofthe controlled object the dynamics of which is given by:
,
, where
and motion resistance function
if
,f(x)=-A if x > 0 where
. That model describes dynamicsof a very important class of industrial installations. As the time-optimalproblem will be understood a transfer of the initial state
to the target state
in a minimumtime
. There has been shown that in the formula defining resistancefunction f(x)there exists a value
that plays an essentialrole in time-optimal structure formation. Namely, if
then thetime-optimal control process is typical, analogous as in classical case
, i.e. there exists a switching curve formed by thetrajectories of time-optimal solutions reaching the target state and thetime-optimal process is formed by at most one switching operation. For the caseA>Abwe will examine two following singular phenomena.(a) If the target state z1=(0, 0) then there exists theswitching curve, dividing the state plane into two sets, however only one itsbranch is formed by the time-optimal solution reaching the target z1=(0, 0) and generated by the control u=-1. None of solution formsthe second branch of switching curve. It is formed by a state-locus dependingon the value of Aonly. In dependency of the starting state z0 thetime-optimal control process is generated by bang-bang control with none,one or two switching operations. This is the first singular phenomenon,because any small decrease of the value Aover A
b requires to change thestructure which would be able to generate the time-optimal process.(b) The paper shows, that if the target state z
1(x_1, 0), x1>0then there exists a set of the starting states from which there start twotrajectories reaching the target in the same minimum time. This is thesecond phenomenon.Finally, some suggestions as to practical applications have been given too. 相似文献
5.
The N-heap Wythoffs game is a two-player impartial game with
N piles of tokens of sizes
Players take turns removing any number of tokens from a single pile, or removing
(a1,..., aN)
from all piles - ai tokens from the i-th pile,
providing that
where is the nim addition. The first player that cannot make a move loses. Denote all the
P-positions (i.e., losing positions) by
Two conjectures were proposed on the game by Fraenkel [7]. When
are fixed, i) there exists an integer N1
such that when
. ii) there exist integers N2
and _2 such that when
, the golden section.In this paper, we provide a sufficient condition for the conjectures to hold, and subsequently
prove them for the three-heap Wythoffs game with the first piles having up to 10 tokens.AMS Subject Classification: 91A46, 68R05. 相似文献
6.
The Rogers L-function
satisfies the functional equation
.From this we derive several other such equations, including Euler's identity L(x)+L(1-x)=L(1) and various identities arising from summation and transformation formulas for basic hypergeometric series. We also obtain some new equations of the form
where is algebraic and the c
k are integers. 相似文献
7.
Gerold Wagner 《Monatshefte für Mathematik》1981,92(3):239-245
Letf be a periodic function on with period 1, piecewise continuously differentiable, satisfying
. For an arbitrary sequence = (
i
) in [0,1) put
and
. If
then
n
(f,) >c· logn holds for some positive constantc (depending onf only) and almost alln. In a certain sense the converse is also true: there is a class of functionsf with
such that
n
(f,) =o (logn).Support has been received from Netherlands Organization for the Advancement of Pure Research (Z. W. O.). 相似文献
8.
Prof P. Szüsz 《Monatshefte für Mathematik》1976,81(2):149-152
A direct proof is given for the following theorem, contained as a special case in a more general result ofPolniakowski:Theorem. Denote
n
the Cesaro-means of order 2 of the sequenceS
1, S2, ... , any real number satisfying 0<<=1. Then
implies
To Prof. Th. Schneider on the occasion of his 65th birthday 相似文献
9.
G. V. Badalyan 《Mathematical Notes》1973,14(5):909-912
It is proved that a known theorem yielding the solution of the Watson problem for a half-plane in terms of the Ostrovskii function remains valid if the Ostrovskii function
is replaced by the function
0} r^x /m (x)$$
" align="middle" border="0">
, where for x [n, n+1) the function m(x)=mn, or by the function
.Translated from Matematicheskie Zametki, Vol. 14, No. 5, pp. 609–614, November, 1973. 相似文献
10.
Y. -F. S. Pétermann 《Monatshefte für Mathematik》1987,103(2):145-157
Let denote the sum-of-divisors function, and set
. Gronwall and Wigert proved (independently) in 1913 and 1914, respectively, thatE
1 (x)= (x log logx). In this paper we obtain the more preciseE
1 (x)=–(x log logx). The method consists in averaging
over suitable arithmetic progressions, and was suggested by the work ofP. Erdös andH. N. Shapiro [Canad. J. Math. 3–4, 375–385 (1951)] on the error term corresponding to Euler's functions,
. 相似文献
11.
Erich Novak 《Numerische Mathematik》1986,50(2):245-252
Summary The definition of the average error of numerical methods (by example of a quadrature formula
to approximateS(f)= f d on a function classF) is difficult, because on many important setsF there is no natural probability measure in the sense of an equidistribution. We define the average a posteriori error of an approximation
by an averaging process over the set of possible information, which is used by
(in the example of a quadrature formula,N(F)={(f(a
1), ...,f/fF} is the set of posible information). This approach has the practical advantage that the averaging process is related only to finite dimensional sets and uses only the usual Lebesgue measure. As an application of the theory I consider the numerical integration of functions of the classF={f:[0,1]/f(x)–f(y)||x–y|}. For arbitrary (fixed) knotsa
i
we determine the optimal coefficientsc
i
for the approximation
and compute the resulting average error. The latter is minimal for the knots
. (It is well known that the maximal error is minimal for the knotsa
i
.) Then the adaptive methods for the same problem and methods for seeking the maximum of a Lipschitz function are considered. While adaptive methods are not better when considering the maximal error (this is valid for our examples as well as for many others) this is in general not the case with the average error. 相似文献
12.
In this work the authors study the conditions for the existence of diffusion equations
13.
U. A. Akramov 《Journal of Mathematical Sciences》1988,43(5):2623-2624
A strong isolation theorem is stated for the case of m3 pairs of complex conjugate linear forms L1(x), ¯L1(x), ..., Lm(x), ¯Lm(x), which define a form
of degree n=2m indecomposable in 2e. This theorem is a direct analog of Skubenko's result for real linear forms [2].Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 151, pp. 5–6, 1986. 相似文献
14.
O. B. Skaskiv 《Ukrainian Mathematical Journal》2004,56(12):1975-1988
We investigate the rate of convergence of series of the form
15.
Summary.
Let
We say that
preserves the distance d 0 if
for each
implies
Let A
n
denote the set of all positive numbers
d such that any map
that preserves unit distance preserves also distance
d.
Let D
n
denote the set of all positive numbers
d with the property: if
and
then there exists a finite set
S
xy
with
such that any map
that preserves unit distance preserves also the distance between
x and y.
Obviously,
We prove:
(1)
(2)
for n 2
D
n
is a
dense subset of
(2) implies that each mapping
f
from
to
(n 2)
preserving unit distance preserves all distances,
if f is continuous with respect to the product topologies
on
and
相似文献
16.
Helena Ferreira 《Extremes》2000,3(4):385-392
Let
be a sequence of identically distributed variables. We study the asymptotic distribution of
, where Y
[r:n] denotes the concomitant of the rth order statistic X
r:n
, corresponding to
, and
is held fixed while
. Conditions are given for the
and
to have the same asymptotic behavior as that we would apply if
were i.i.d. The result is illustrated with a simple linear regression model
, where
is a stationary sequence with extremal index
. 相似文献
17.
Consider a path-integral
which is the solution to a diffusion version of the generalized Schro¨dinger's equation
. Here
, where A is an infinitesimal generator of a strongly continuous Markov Semigroup corresponding to the diffusion process
. For
and V replaced by
one obtains
, which represents a quantum mechanical Hamiltonian corresponding to a particle of mass 1 (in atomic units) subject to interaction with potential V. This paper is concerned with computer calculations of the second eigenvalue of
by generating a large number of trajectories of an ergodic diffusion process. 相似文献
18.
In this paper, we analyze a class of methods for minimizing a proper lower semicontinuous extended-valued convex function
. Instead of the original objective function f, we employ a convex approximation f
k
+ 1 at the kth iteration. Some global convergence rate estimates are obtained. We illustrate our approach by proposing (i) a new family of proximal point algorithms which possesses the global convergence rate estimate
even it the iteration points are calculated approximately, where
are the proximal parameters, and (ii) a variant proximal bundle method. Applications to stochastic programs are discussed. 相似文献
19.
K. ONO 《Compositio Mathematica》1997,106(3):349-360
If E is an elliptic curve over
, then let E(D) denote theD-quadratic twist of E. It is conjectured that there are infinitely many primesp for which E(p) has rank 0, and that there are infinitely many primes
for which
has positive rank. For some special curvesE we show that there is a set S of primes p with density
for which if
is a squarefree integer where
, then E(D) has rank 0. In particular E(p) has rank 0 for every
. As an example let E1 denote the curve
.Then its associated set of primes S1 consists of the prime11 and the primes p for which the order of the reduction ofX0(11) modulo p is odd. To obtain the general result we show for primes
that the rational factor of L(E(p),1) is nonzero which implies thatE(p) has rank 0. These special values are related to surjective
Galois representations that are attached to modularforms. Another example of this result is given, and we conclude with someremarks regarding the existence of positive rank prime twists via polynomialidentities. 相似文献
20.
Qi S. Zhang 《Journal of Computational Analysis and Applications》2000,2(4):277-292
We study the inhomogeneous semilinear wave equations
on
with initial values
and
,where
is a noncompact, complete manifold. We founda new critical behavior in the following sense. There exists ap* > 0. When 1 < p p*, the above problem hasno global solution for any nonnegative
not identicallyzero and for any
and
; when
the problem has a global solution for some
and some
and
. If
, which is equipped with the Euclideanmetric, then
. If
we show that
belongs to the blow upcase. Although homogeneous semilinear wave equations are known to exhibit acritical behavior for a long time, this seems to be the first result oninhomogeneous ones. 相似文献
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