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1.
Joseph Rosenblatt 《Mathematische Annalen》1977,230(3):245-272
For a mean zero norm one sequence (f
n
)L
2[0, 1], the sequence (f
n
{nx+y}) is an orthonormal sequence inL
2([0, 1]2); so if
, then
converges for a.e. (x, y)[0, 1]2 and has a maximal function inL
2([0, 1]2). But for a mean zerofL
2[0, 1], it is harder to give necessary and sufficient conditions for theL
2-norm convergence or a.e. convergence of
. Ifc
n
0 and
, then this series will not converge inL
2-norm on a denseG
subset of the mean zero functions inL
2[0, 1]. Also, there are mean zerofL[0, 1] such that
never converges and there is a mean zero continuous functionf with
a.e. However, iff is mean zero and of bounded variation or in some Lip() with 1/2<1, and if |c
n
| = 0(n
–) for >1/2, then
converges a.e. and unconditionally inL
2[0, 1]. In addition, for any mean zerof of bounded variation, the series
has its maximal function in allL
p[0, 1] with 1p<. Finally, if (f
n
)L
[0, 1] is a uniformly bounded mean zero sequence, then
is a necessary and sufficient condition for
to converge for a.e.y and a.e. (x
n
)[0, 1]. Moreover, iffL
[0, 1] is mean zero and
, then for a.e. (x
n
)[0, 1],
converges for a.e.y and in allL
p
[0, 1] with 1p<. Some of these theorems can be generalized simply to other compact groups besides [0, 1] under addition modulo one. 相似文献
2.
Suppose that A is an n × n nonnegative matrix whose eigenvalues are = (A), 2, ..., n. Fiedler and others have shown that \det( I -A) n - n, for all > with equality for any such if and only if A is the simple cycle matrix. Let a
i be the signed sum of the determinants of the principal submatrices of A of order i × i, i=1, ..., n - 1. We use similar techniques to Fiedler to show that Fiedler's inequality can be strengthened to:
for all . We use this inequality to derive the inequality that:
. In the spirit of a celebrated conjecture due to Boyle-Handelman, this inequality inspires us to conjecture the following inequality on the nonzero eigenvalues of A: If 1 = (A), 2,...,k
are (all) the nonzero eigenvalues of A, then
. We prove this conjecture for the case when the spectrum of A is real. 相似文献
3.
Aparna W. Higgins 《Algebra Universalis》1985,20(2):179-193
Given a group G and a descending chainG
0,G
1,...,G
n, of normal subgroups ofG, we prove that there exists a universal algebra
, such that the chain ...Wn(
)...W1(
}) W0(
)W(
) is isomorphic to the chain ...G
n ...G
1G
0G, where W(
) is the group of weak automorphisms of
, and Wn(
) is the group of weak automorphisms of
that leaves alln-ary operations fixed.We also prove that there are an infinite number of non-isomorphic algebras that satisfy the above.These results are a generalization of those proved by J. Sichler, in the special case when G=G0, and G1=G2=...=Gn=....Presented by J. Mycielski.This paper comprises part of the author's doctoral dissertation at the University of Notre Dame in 1983. The author wishes to express her deep gratitude to Professor Abraham Goetz for suggesting this problem, for being extremely generous with his time and experience, and for giving her his constant encouragement. The author also thanks the reviewer for his helpful comments. 相似文献
4.
Let w() be a positive weight function on the unit circle of the complex plane. For a sequence of points {
k
}
k = 1
included in a compact subset of the unit disk, we consider the orthogonal rational functions
n
that are obtained by orthogonalization of the sequence { 1, z / 1, z
2 / 2, ... } where
, with respect to the inner product
In this paper we discuss the behaviour of
n
(t) for t = 1 and n under certain conditions. The main condition on the weight is that it satisfies a Lipschitz–Dini condition and that it is bounded away from zero. This generalizes a theorem given by Szeg in the polynomial case, that is when all
k
= 0. 相似文献
5.
P. Cubiotti 《Journal of Optimization Theory and Applications》1997,92(3):477-495
Given a nonempty set
and two multifunctions
, we consider the following generalized quasi-variational inequality problem associated with X, : Find
such that
. We prove several existence results in which the multifunction is not supposed to have any continuity property. Among others, we extend the results obtained in Ref. 1 for the case (x(X. 相似文献
6.
Dr. Karl Umgeher 《Monatshefte für Mathematik》1976,81(4):311-314
We consider the set of regular functions
. We construct a Borel measure and a class of outer measures
h
onH. With these and
h
we show that: (HS)=0 and
h
(HS)=0, (S is the set of normed univalent functions). From
h
(HS)=0 follows—forh=t
—that the Hausdorff—Billingsley-dimension ofHS is zero. 相似文献
7.
Let T be a regular operator from L
p L
p. Then
, where Tr denotes the regular norm of T, i.e., Tr=|T| where |T| denotes the modulus operator of a regular operator T. For p=1 every bounded linear operator is regular and T=Tr, so that the above inequality generalizes the Daugavet equation for operators on L
1–spaces. The main result of this paper (Theorem 9) is a converse of the above result. Let T be a regular linear operator on L
p and denote by T
A the operator TA. Then
for all A with (A)>0 if and only if
. 相似文献
8.
Philip Ehrlich 《Algebra Universalis》1988,25(1):7-16
An -universally extending ordered field of power is constructed for each regular power where 0 < On and
. When is inaccessible, the structure is either a (set) model of J. H. Conway's ordered field No or an isomorphic copy of No depending on whether or not is a set or a proper class.Presented by Jan Mycielski. 相似文献
9.
Martin Goldstern 《Monatshefte für Mathematik》1993,116(3-4):237-243
IfC is a Polish probability space,
a Borel set whose sectionsW
x ( have measure one and are decreasing
, then we show that the set
x
W
x
has measure one. We give two proofs of this theorem—one in the language of set theory, the other in the language of probability theory, and we apply the theorem to a question on completely uniformly distributed sequences.Supported by DFG grant Ko 490/7-1. 相似文献
10.
Pavel Valtr 《Discrete and Computational Geometry》1992,7(1):135-152
For a finite setA of points in the plane, letq(A) denote the ratio of the maximum distance of any pair of points ofA to the minimum distance of any pair of points ofA. Fork>0 letc
(k) denote the largest integerc such that any setA ofk points in general position in the plane, satisfying
for fixed
, contains at leastc convex independent points. We determine the exact asymptotic behavior ofc
(k), proving that there are two positive constants=(), such thatk
1/3c
(k)k
1/3. To establish the upper bound ofc
(k) we construct a set, which also solves (affirmatively) the problem of Alonet al. [1] about the existence of a setA ofk points in general position without a 7-hole (i.e., vertices of a convex 7-gon containing no other points fromA), satisfying
. The construction uses Horton sets, which generalize sets without 7-holes constructed by Horton and which have some interesting properties. 相似文献
11.
Denote by
the class of all triangle-free
graphs on n vertices and
m edges. Our main result is
the following sharp threshold, which answers the question for
which densities a typical triangle-free graph is bipartite. Fix
> 0 and let
. If
n/2 m (1 – ) t
3, then almost
all graphs in
are not bipartite, whereas if
m (1 + )t
3, then almost
all of them are bipartite. For m (1 + )t
3, this allows
us to determine asymptotically the number of graphs in
. We also obtain corresponding
results for C
-free graphs, for any
cycle C
of fixed odd length.
Forschergruppe Algorithmen, Struktur, Zufall
supported by Deutsche Forschungsgemeinschaft grant FOR
413/1-1 相似文献
12.
Jean-Pierre Kahane Jacques Peyrière Wen Zhi-ying Wu Li-ming 《Probability Theory and Related Fields》1988,79(4):625-628
Summary Let be a bounded function on such that
converges towards l as n goes to infinity, uniformly with respect to m. Let {X
n} be a random walk on , not concentrated on a proper subgroup of Then, with probability 1,
converges towards l as n goes to infinity. The result also holds for any countable abelian group instead of . Other modes of convergence are considered (Cesaro convergence of order >1/2). The Cesaro convergence of expressions such that (X
n) (X
n+1) is also investigated. 相似文献
13.
Let (X
n
)
0 be a Markov chain with state space S=[0,1] generated by the iteration of i.i.d. random logistic maps, i.e., X
n+1=C
n+1
X
n
(1–X
n
),n0, where (C
n
)
1 are i.i.d. random variables with values in [0, 4] and independent of X
0. In the critical case, i.e., when E(log C
1)=0, Athreya and Dai(2) have shown that X
n
P
0. In this paper it is shown that if P(C
1=1)<1 and E(log C
1)=0 then(i) X
n
does not go to zero with probability one (w.p.1) and in fact, there exists a 0<<1 and a countable set (0,1) such that for all xA(0,1), P
x
(X
n
for infinitely many n1)=1, where P
x
stands for the probability distribution of (X
n
)
0 with X
0=x w.p.1. A is a closed set for (X
n
)
0.(ii) If is the supremum of the support of the distribution of C
1, then for all xA
(a)
for 12(b)
for 24(c)
for 24 under some additional smoothness condition on the distribution of C
1.(iii) The empirical distribution
converges weakly to
0, the delta measure at 0, w.p.1 for any initial distribution of X
0. 相似文献
14.
Noboru Hamada 《Designs, Codes and Cryptography》1997,10(1):41-56
Let k and d be any integers such that k 4 and
. Then there exist two integers and in {0,1,2} such that
. The purpose of this paper is to prove that (1) in the case k 5 and (,) = (0,1), there exists a ternary
code meeting the Griesmer bound if and only if
and (2) in the case k 4 and (,) = (0,2) or (1,1), there is no ternary
code meeting the Griesmer bound for any integers k and d and (3) in the case k 5 and
, there is no projective ternary
code for any integers k and such that 1k-3, where
and
for any integer i 0. In the special case k=6, it follows from (1) that there is no ternary linear code with parameters [233,6,154] , [234,6,155] or [237,6,157] which are new results. 相似文献
15.
William D. L. Appling 《Annali di Matematica Pura ed Applicata》1985,140(1):147-154
Summary Suppose U is a set,F is a field of subsets of U, pAB is the set of all real-valued bounded finitely additive functions defined onF, and for each in pAB, A()={: in pAB, absolutely continuous with respect to }. SupposeM is a linear subspace of pAB such that
. A generalisation of a previously discussed collection of linear transformations (see J. London Math. Soc., vol. 44 (1969), pp. 385–396) is treated by letting CM denote the set to which T belongs iff T is a linear transformation from M into pAB such that for some K inR and all in M and V inF,
. Certain theorems of the aforementioned reference are generalized, as well as one of Trans. Amer. Math. Soc., vol. 199, (1974), pp. 131–140. The principal result of the present paper is the following generalisation of a reversibility characterisation in the first mentioned reference: Theorem: If T is in CM, then (, T()): in M A(T()) is the only reversible subset T0 if T such that: i) the domain M0 of T0 is a linear subspace of M and
, and ii) the range of T0 is the range of T. 相似文献
16.
Micheline Vigué-Poirrier 《manuscripta mathematica》1986,56(2):177-191
Let X be a nilpotent space such that it exists k1 with Hp (X,) = 0 p > k and Hk (X,) 0, let Y be a (m–1)-connected space with mk+2, then the rational homotopy Lie algebra of YX (resp.
is isomorphic as Lie algebra, to H* (X,) (* (Y) ) (resp.+ (X,) (* (Y) )). If X is formal and Y -formal, then the spaces YX and
are -formal. Furthermore, if dim * (Y) is infinite and dim H* (Y,Q) is finite, then the sequence of Betti numbers of
grows exponentially. 相似文献
17.
Let
be the prime factorization of a positive integer k and let b
k
(n) denote the number of partitions of a non-negative integer n into parts none of which are multiples of k. If M is a positive integer, let S
k
(N; M) be the number of positive integers N for which b
k(n
) 0(mod
M). If
we prove that, for every positive integer j
In other words for every positive integer j,
b
k(n) is a multiple of
for almost every non-negative integer n. In the special case when k=p is prime, then in representation-theoretic terms this means that the number ofp -modular irreducible representations of almost every symmetric groupS
n is a multiple of p
j. We also examine the behavior of b
k(n) (mod
) where the non-negative integers n belong to an arithmetic progression. Although almost every non-negative integer n (mod t) satisfies b
k(n) 0 (mod
), we show that there are infinitely many non-negative integers n r (mod t) for which b
k(n) 0 (mod
) provided that there is at least one such n. Moreover the smallest such n (if there are any) is less than 2
. 相似文献
18.
On the Harris Recurrence of Iterated Random Lipschitz Functions and Related Convergence Rate Results 总被引:1,自引:0,他引:1
Gerold Alsmeyer 《Journal of Theoretical Probability》2003,16(1):217-247
A result by Elton(6) states that an iterated function system
of i.i.d. random Lipschitz maps F
1,F
2,... on a locally compact, complete separable metric space
converges weakly to its unique stationary distribution if the pertinent Liapunov exponent is a.s. negative and
for some
. Diaconis and Freedman(5) showed the convergence rate be geometric in the Prokhorov metric if
for some p>0, where L
1 denotes the Lipschitz constant of F
1. The same and also polynomial rates have been recently obtained in Alsmeyer and Fuh(1) by different methods. In this article, necessary and sufficient conditions are given for the positive Harris recurrence of (M
n
)
n0 on some absorbing subset
. If
and the support of has nonempty interior, we further show that the same respective moment conditions ensuring the weak convergence rate results mentioned above now lead to polynomial, respectively geometric rate results for the convergence to in total variation or f-norm
f
, f(x)=1+d(x,x
0)
for some (0,p]. The results are applied to various examples that have been discussed in the literature, including the Beta walk, multivariate ARMA models and matrix recursions. 相似文献
19.
J. C. Lagarias 《Monatshefte für Mathematik》1993,115(4):299-328
Given a vector of real numbers=(1,...
d
)
d
, the Jacobi-Perron algorithm and related algorithms, such as Brun's algorithm and Selmer's algorithm, produce a sequence of (d+1)×(d+1) convergent matrices {C(n)():n1} whose rows provide Diophantine approximations to . Such algorithms are specified by two mapsT:[0, 1]
d
[0, 1]
d
and A:[0,1]
d
GL(d+1,), which compute convergent matrices C(n)())...A(T())A(). The quality of the Diophantine approximations these algorithms find can be measured in two ways. The best approximation exponent is the upper bound of those values of for which there is some row of the convergent matrices such that for infinitely many values ofn that row of C(n)() has
. The uniform approximation exponent is the upper bound of those values of such that for all sufficiently large values ofn and all rows of C(n)() one has
. The paper applies Oseledec's multiplicative ergodic theorem to show that for a large class of such algorithms and take constant values and on a set of Lebesgue measure one. It establishes the formula where are the two largest Lyapunov exponents attached by Oseledec's multiplicative ergodic theorem to the skew-product (T, A,d), whered is aT-invariant measure, absolutely continuous with respect to Lebesgue measure. We conjecture that holds for a large class of such algorithms. These results apply to thed-dimensional Jacobi-Perron algorithm and Selmer's algorithm. We show that; experimental evidence of Baldwin (1992) indicates (nonrigorously) that. We conjecture that holds for alld2. 相似文献
20.
D. M. Smirnov 《Algebra and Logic》2004,43(4):249-257
For integers 1 m < n, a Cantor variety with m basic n-ary operations i and n basic m-ary operations k is a variety of algebras defined by identities k(1(
), ... , m(
)) =
k and i(1(
), ... ,n(
)) = y
i, where
= (x
1., ... , x
n) and
= (y
1, ... , y
m). We prove that interpretability types of Cantor varieties form a distributive lattice, , which is dual to the direct product 1 × 2 of a lattice, 1, of positive integers respecting the natural linear ordering and a lattice, 2, of positive integers with divisibility. The lattice is an upper subsemilattice of the lattice
of all interpretability types of varieties of algebras. 相似文献