共查询到20条相似文献,搜索用时 15 毫秒
1.
Sirous Moradi 《Annali dell'Universita di Ferrara》2012,58(1):119-125
In this paper we provide a simple proof of the existence coupled fixed point theorem in complete cone metric spaces due to Sabetghadam et al. (Fixed Point Theory Appl 2009:8, 2009) and due to Olatinwo (Annali Dell’Universita’Di Ferrara 57:173–180, 2011). In particular we prove that these results are spacial cases of Rezapour and Hamlbarani’s theorems (J Math Anal Appl 345(2):719–724, 2008). 相似文献
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Daniel Schultz 《The Ramanujan Journal》2014,34(1):119-128
A short and simple proof of the Rogers–Selberg identities is obtained from the work of Andrew Sills on identities of the Rogers–Ramanujan type. 相似文献
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In this article we present a simple and elegant algebraic proof of Pascal’s hexagon theorem which requires only knowledge of basics on conic sections without theory of projective transformations. Also, we provide an efficient algorithm for finding an equation of the conic containing five given points and a criterion for verification whether a set of points is a subset of the conic. 相似文献
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The Craig–Sakamoto theorem establishes the independence of two quadratic forms in normal variates. In this article, we provide a simple proof of a generalized Craig–Sakamoto theorem. 相似文献
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In this paper we give a simple proof of an inequality for intermediate Diophantine exponents obtained recently by W.M. Schmidt and L. Summerer. 相似文献
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We prove a quantitative version of the Gibbard-Satterthwaite theorem. We show that a uniformly chosen voter profile for a neutral social choice function f of q ?? 4 alternatives and n voters will be manipulable with probability at least 10?4??2 n ?3 q ?30, where ?? is the minimal statistical distance between f and the family of dictator functions. Our results extend those of [11], which were obtained for the case of 3 alternatives, and imply that the approach of masking manipulations behind computational hardness (as considered in [4,6,9,15,7]) cannot hide manipulations completely. Our proof is geometric. More specifically it extends the method of canonical paths to show that the measure of the profiles that lie on the interface of 3 or more outcomes is large. To the best of our knowledge our result is the first isoperimetric result to establish interface of more than two bodies. 相似文献
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It is well known that certain properties of continuous functions on the circle T related to the Fourier expansion can be improved by a change of variable, i.e., by a homeomorphism of the circle onto itself. One of the results in this area is the Jurkat–Waterman theorem on conjugate functions, which improves the classical Bohr–Pál theorem. In the present work we propose a short and technically very simple proof of the Jurkat–Waterman theorem. Our approach yields a stronger result. 相似文献
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We present an elementary proof of the Karush–Kuhn–Tucker Theorem for the problem with nonlinear inequality constraints and
linear equality constraints. Most proofs in the literature rely on advanced optimization concepts such as linear programming
duality, the convex separation theorem, or a theorem of the alternative for systems of linear inequalities. By contrast, the
proof given here uses only basic facts from linear algebra and the definition of differentiability. 相似文献
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A proof of Sethares'''' conjecture 总被引:1,自引:0,他引:1
YAO GuowuSchool of Mathematical Sciences Peking University Beijing China 《中国科学A辑(英文版)》2004,47(2):236-244
Let (?)(z) be holomorphic in the unit disk △ and meromorphic on △. Suppose / is a Teichmuller mapping with complex dilatation In 1968, Sethares conjectured that f is extremal if and only if either (i)(?) has a double pole or (ii)(?) has no pole of order exceeding two on (?)△. The "if" part of the conjecture had been solved by himself. We will give the affirmative answer to the "only if" part of the conjecture. In addition, a more general criterion for extremality of quasiconformal mappings is constructed in this paper, which generalizes the "if" part of Sethares' conjecture and improves the result by Reich and Shapiro in 1990. 相似文献
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ABSTRACT We introduce semidirect and wreath products of finite ordered semigroups and extend some standard decomposition results to this case. 相似文献
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In this paper we characterize the (commutative) Priifer rings that can be realized as endomorphism rings of artinian modules over arbitrary associative rings with identity (Theorem 4.7). This characterization is obtained by determining the structure of ∑-pure-injective modules over Prufer rings (Theorems 3.4 and 3.5) 相似文献
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Bodan Arsovski 《Israel Journal of Mathematics》2011,182(1):505-508
We prove Snevily’s conjecture, which states that for any positive integer k and any two k-element subsets {a
1, …, a
k
} and {b
1, …, b
k
} of a finite abelian group of odd order there exists a permutation π ∈ S
k
such that all sums a
i
+ b
π(i) (i ∈ [1, k]) are pairwise distinct. 相似文献
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Eli Glasner 《Israel Journal of Mathematics》1997,102(1):13-27
We present simple characterizations of the setsE
μ andE
X
of measure entropy pairs and topological entropy pairs of a topological dynamical system (X, T) with invariant probability measureμ. This characterization is used to show that the set of (measure) entropy pairs of a product system coincides with the product
of the sets of (measure) entropy pairs of the component systems; in particular it follows that the product of u.p.e. systems
(topological K-systems) is also u.p.e. Another application is to show that the proximal relationP forms a residual subset of the setE
X
. Finally an example of a minimal point distal dynamical system is constructed for whichE
X
∩(X
0×X
0)≠
, whereX
0 is the denseG
δ subset of distal points inX. 相似文献