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对任意实数λ∈[0,1],在区间[0,1]上构造一个连续自映射,使得它有一个由传递点构成的且Lebesgue测度为1的D_λ-攀援集.这加强了分布混沌的相应结论. 相似文献
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称由正整数集的某些子集构成的一个集合为一个 Furstenberg族, 如果它满足向上遗传的要求(即包含着族中某一个成员的正整数的子集也是这个族的成员). 给定一个系统 (即一个完备度量空间和其上的一个连续映射构成的偶对), 对于Furstenberg 族F, 将称空间中某些点的偶对为F-攀援偶对,使得众所周知的 Li-Yorke攀援偶对和分布式攀援偶对都成为某种特定的F-攀援偶对. 文中对F-攀援偶对构成的集合作了一般性探讨. 定义了全局性F-混沌系统和全局性强F-混沌系统, 并且对于系统是否是全局性强F-混沌的给出了一个判据. 相似文献
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张颖 《数学的实践与认识》2017,(5):247-250
设β1为实数,T_β为[0,1]的β变换.攀援集的任何两个点随着时间的转移会越来越接近但同时又总能在任意长时间后保持一定的距离.证明了在Lebesgue测度意义下关于T_β的攀援集是一个零测集.Distal点对的两个点表示随着时间的转移始终保持着一定的距离.如果固定其中一个点x_0,所有满足x∈[0,1)且lim inf n→∞|T_β~n(x)-T_β~n(x_0)|0的点称为关于x_0的distal集,如果把这个集合记为R_β(x_0),根据Borel-Cantelli引理得到R_β(x_0)的Lebesgue测度为零. 相似文献
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提出了一种基于不变集切换的非线性系统鲁棒预测控制算法.采用分段蕴含方法将非线性系统动态用一组线性变参数(LPV)系统动态包裹;计算出非线性系统的平衡面,对于每个LPV蕴含模型,针对相应的平衡点构造多面体不变集,得到覆盖非线性系统平衡面的一组相互重叠的不变集;在线根据系统当前状态所处的不变集和LPV区间切换控制律,最终保证闭环系统的稳定性.与传统的非线性预测控制相比,这种方法在构造不变集和确定控制律的计算都是离线进行,而在线只需根据当前状态切换控制律即可,从而避免了求解复杂的非凸非线性规划,在很大程度上降低了在线计算量. 相似文献
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具有变时滞Hopfield型神经网络的正不变集与吸引集 总被引:2,自引:0,他引:2
研究了具有变时滞Hopfield型神经网络的正不变集与吸引集,获得了正不变集与吸引集存在性的充分判据。 相似文献
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李文波 《数学的实践与认识》2015,(6):306-310
研究一般拓扑动力系统的复杂性是很困难的,拓扑共轭、拓扑半共轭、嵌入映射和转移不变集都可以不同程度保持动力系统的复杂性.通过研究拓扑动力系统与符号动力系统拓扑共轭,找到了拓扑动力(子)系统存在转移不变集的条件,同时证明了拓扑动力系统存在转移不变集与乘积拓扑动力系统存在转移不变集的关系,通过研究相对简单、直观的符号动力系统,间接的反应一般拓扑动力(子)系统与其乘积拓扑动力系统的动力性状. 相似文献
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In this paper, we continue the study of paired-domination in graphs introduced by Haynes and Slater [T.W. Haynes, P.J. Slater, Paired-domination in graphs, Networks 32 (1998), 199–206]. A paired-dominating set of a graph G with no isolated vertex is a dominating set S of vertices whose induced subgraph has a perfect matching. We consider paired-dominating sets which are also locating sets, that is distinct vertices of G are dominated by distinct subsets of the paired-dominating set. We consider three variations of sets which are paired-dominating and locating sets and investigate their properties. 相似文献
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Building sets are a successful tool for constructing semi‐regular divisible difference sets and, in particular, semi‐regular relative difference sets. In this paper, we present an extension theorem for building sets under simple conditions. Some of the semi‐regular relative difference sets obtained using the extension theorem are new in the sense that their ambient groups have smaller ranks than previously known. © 2000 John Wiley & Sons, Inc. J Combin Designs 8: 50–57, 2000 相似文献
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James H. Schmerl 《Mathematical Logic Quarterly》1998,44(4):515-521
There is a recursive set of natural numbers which is the difference set of some recursively enumerable set but which is not the difference set of any recursive set. 相似文献
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研究如何将任意有限域上的多项式集分解为有限多个简单列.为了解决这一问题,首先研究简单列和根理想之间的关系,然后基于已有的正则分解算法和有限域上理想的根的两种计算方法设计一个有限域上多项式集的简单分解算法.计算试验表明,文章给出的算法是有效的. 相似文献
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A. N. Degtev 《Mathematical Notes》1999,66(2):148-152
LetA be a subset of
, and leta∉A. The setA is said to be almost semirecursive, if there is a two-place general recursive functionf such thatf(x, y)ε{x, y, a}∧({x, y}⊆A⇌f(x, y)εA) for all
. Among other facts, it is proved that ifA and
are almost semirecursive sets, thenA is a semirecursive set, and that there exists a wsr*-set that is neither a wsr-nor an almost semirecursive set.
Translated fromMatematicheskie Zametki, Vol. 66, No. 2, pp. 188–193, August, 1999. 相似文献
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A subset A of a group G is sum-free if a + b does not belong to A for any a, b ∈ A. Asymptotics of the number of sum-free sets in groups of prime order are proved. 相似文献
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We prove that every hesitant fuzzy set on a set E can be considered either a soft set over the universe or a soft set over the universe E. Concerning converse relationships, for denumerable universes we prove that any soft set can be considered even a fuzzy set. Relatedly, we demonstrate that every hesitant fuzzy soft set can be identified with a soft set, thus a formal coincidence of both notions is brought to light. Coupled with known relationships, our results prove that interval type-2 fuzzy sets and interval-valued fuzzy sets can be considered as soft sets over the universe . Altogether we contribute to a more complete understanding of the relationships among various theories that capture vagueness and imprecision. 相似文献
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Osmo Kaleva 《Fuzzy Sets and Systems》1985,15(1):99-100
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