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841.
Steen Pedersen 《Proceedings of the American Mathematical Society》2004,132(7):2095-2101
Suppose that where are real numbers such that and The union is not assumed to be disjoint. It is shown that the translates , , tile the real line for some bounded measurable set if and only if the exponentials , , form an orthogonal basis for some bounded measurable set
842.
C-H. Chu R. V. Hü gli M. Mackey 《Proceedings of the American Mathematical Society》2004,132(11):3305-3308
Let be the Banach algebra of bounded holomorphic functions on the open unit ball of a Banach space. We show that the identity operator is an isolated point in the space of composition operators on . This answers a conjecture of Aron, Galindo and Lindström.
843.
In his 1961 paper, Marcel Golay showed how the search for pairs of binary sequences of length with complementary autocorrelation is at worst a problem. Andres, in his 1977 master's thesis, developed an algorithm which reduced this to a search and investigated lengths up to 58 for existence of pairs. In this paper, we describe refinements to this algorithm, enabling a search at length 82. We find no new pairs at the outstanding lengths 74 and 82. In extending the theory of composition, we are able to obtain a closed formula for the number of pairs of length generated by a primitive pair of length . Combining this with the results of searches at all allowable lengths up to 100, we identify five primitive pairs. All others pairs of lengths less than 100 may be derived using the methods outlined.
844.
Zaqueu Coelho 《Transactions of the American Mathematical Society》2004,356(11):4427-4445
For a minimal circle homeomorphism we study convergence in law of rescaled hitting time point process of an interval of length 0$">. Although the point process in the natural time scale never converges in law, we study all possible limits under a subsequence. The new feature is the fact that, for rotation numbers of unbounded type, there is a sequence going to zero exhibiting coexistence of two non-trivial asymptotic limit point processes depending on the choice of time scales used when rescaling the point process. The phenomenon of loss of tightness of the first hitting time distribution is an indication of this coexistence behaviour. Moreover, tightness occurs if and only if the rotation number is of bounded type. Therefore tightness of time distributions is an intrinsic property of badly approximable irrational rotation numbers.
845.
Ka Hin Leung Siu Lun Ma Bernhard Schmidt 《Transactions of the American Mathematical Society》2004,356(11):4343-4358
In 1963 Ryser conjectured that there are no circulant Hadamard matrices of order 4$"> and no cyclic difference sets whose order is not coprime to the group order. These conjectures are special cases of Lander's conjecture which asserts that there is no abelian group with a cyclic Sylow -subgroup containing a difference set of order divisible by . We verify Lander's conjecture for all difference sets whose order is a power of a prime greater than 3.
846.
For any subset A of the unit sphere of a Banach space X and for [0,2) the notion of -flatness is introduced as a measure of non-flatness of A. For any positive , construction of locally finite tilings of the unit sphere by -flat sets is carried out under suitable -renormings of X in a quite general context; moreover, a characterization of spaces having separable dual is provided in terms of the existence of such tilings. Finally, relationships between the possibility of getting such tilings of the unit sphere in the given norm and smoothness properties of the norm are discussed. 相似文献
847.
JieLU JinChengXIONG JianCHEN 《数学学报(英文版)》2004,20(3):415-422
Let G be a graph which contains exactly one simple closed curve. We prove that a continuous map f : G → G has zero topological entropy if and only if there exist at most k ≤ |(Edg(G) End(G) 3)/2] different odd numbers n1,...,nk such that Per(f) is contained in ∪i=1^k ∪j=0^∞ ni2^j, where Edg(G) is the number of edges of G and End(G) is the number of end points of G. 相似文献
848.
Abstract
We prove that there are non-recursive r.e. sets
A and C with A <
T
C such that for every set
.
Both authors are supported by “863” and the National
Science Foundation of China 相似文献
849.
Let I = [0, 1], c
1, c
2 ∈ (0, 1) with c
1 < c
2 and f : I⊸I be a continuous map satisfying:
are both strictly increasing and
is strictly decreasing. Let A = {x ∈ [0, c
1]∣f(x) = x},
a=max A, a
1 =max(A\{a}), and B = {x ∈ [c
2, 1]∣f(x) = x}, b=minB, b
1 =min(B\{b}). Then the inverse
limit (I, f) is an arc if and only if one of the following three conditions holds:
(1) If c
1 < f (c
1) ≤ c
2 (resp. c
1 ≤ f (c
2) < c
2), then f has a single fixed point, a period two orbit,
but no points of period greater than two or f has more than one fixed point but no points of other periods, furthermore, if A≠φ and B≠φ, then f (c
2) > a (resp. f (c
1) < b).
(2) If f (c
1) ≤ c
1 (resp. f (c
2) ≥ c
2), then f has more than one fixed point, furthermore, if B≠φ and A\ {a} ≠φ, f (c
2) ≥ a or if a
1 < f (c
2) < a, f
2 (c
2) > f (c
2), (resp. f has more than one fixed point, furthermore, if A≠φ and B\{b}≠φ, f (c
1) ≤ b or if b < f (c
2) < b
1, f
2 (c
1) < f (c
1)).
(3) If f (c
1) > c
2 and f (c
2) < c
1, then f has a single fixed point, a single period two orbit lying in I\(u, v) but no points of period greater than two, where u, v ∈ [c
1, c
2] such that f (u) = c
2 and f (v) = c
1.
Supported by the National Natural Science Foundation of China (No. 19961001, No. 60334020) and Outstanding Young Scientist
Research Fund. (No. 60125310) 相似文献
850.
FangWANG ShiHongCHENG 《数学学报(英文版)》2004,20(5):869-878
We obtain an almost sure central limit theorem (ASCLT) for heavily trimmed sums. We also prove a function-typed ASCLT under the same conditions that assure measurable functions to satisfy the ASCLT for the partial sums of i.i.d, random variables with E X1 = 0, EX1^2 = 1. 相似文献