共查询到20条相似文献,搜索用时 15 毫秒
1.
Josef Niederle 《Order》2008,25(1):1-8
Super-relational fixed point property for ordered sets is formulated. It is weaker than the strengthened fixed point property
and stronger than the product property.
Presented at the Summer School on General Algebra and Ordered Sets, Radějov, 3–9 September 2006. 相似文献
2.
Bernd S. W. Schröder 《Order》2006,23(2-3):211-219
This note presents examples of non-dismantlable ordered sets P with the fixed point property such that P
A
with A an arbitrary antichain and P
C
with C being a four crown have the fixed point property. 相似文献
3.
For a compact connected group G, in a compact free G-space M every closed subset is the fixed point set of an autohomeomorphism if the weight of M is not bigger than that of G. In a compact group with nonsingleton components, every closed subset is the fixed point set of an autohomeomorphism if and only if the weight of the whole group is not bigger than that of the component of the identity. 相似文献
4.
Bernd S. W. Schröder 《Order》2017,34(2):307-322
We provide a polynomial time algorithm that identifies if a given finite ordered set is in the class of d2-collapsible ordered sets. For a d2-collapsible ordered set, the algorithm also determines if the ordered set is connectedly collapsible. Because finite ordered sets of interval dimension 2 are d2-collapsible, in particular, the algorithm determines in polynomial time if a given finite ordered set of interval dimension 2 has the fixed point property. This result is also a first step in investigating the complexity status of the question whether a given collapsible ordered set has the fixed point property. 相似文献
5.
In this paper, we first show that for every mapping $f$ from a metric space $Ω$ to itself which is continuous off a countable subset of $Ω,$ there exists a nonempty
closed separable subspace $S ⊂ Ω$ so that $f|_S$ is again a self mapping on $S.$ Therefore,
both the fixed point property and the weak fixed point property of a nonempty closed
convex set in a Banach space are separably determined. We then prove that every
separable subspace of $c_0(\Gamma)$ (for any set $\Gamma$) is again lying in $c_0.$ Making use of these
results, we finally presents a simple proof of the famous result: Every non-expansive
self-mapping defined on a nonempty weakly compact convex set of $c_0(\Gamma)$ has a fixed
point. 相似文献
6.
Imed Zaguia 《Order》2008,25(3):267-279
The purpose of this paper is to investigate how the fixed point property and its negation behave when a covering relation
is added to the order. We prove that every finite ordered set which is not totally ordered and which is dismantlable by retractables,
respectively by irreducibles, has an upper cover (in its extension lattice) which is also dismantlable by retractables, respectively
by irreducibles. We also provide examples of finite ordered sets having the fixed point property so that none of their upper
covers has the fixed point property.
Part of this work was done while the author was visiting Brandon University. The author thanks M. Roddy for his hospitality
and financial support. 相似文献
7.
8.
In this paper, we discuss the concept of fixed point curve for linear interpolations of weakly inward contractions and establish necessary condition for a nonex- pansive mapping to have approximate fixed point property. 相似文献
9.
10.
Order - We prove that, for a finite ordered set P that contains no crowns with 6 or more elements, it can be determined in polynomial time if P has the fixed point property. This result is obtained... 相似文献
11.
引入了L-空间和L-空间上的KKM类映射,建立了关于该类映射的一些不动点定理,其中包括Schauder型和Fan-Browder型不动点定理.得到了L-空间中的KyFan匹配定理和叠合点定理. 相似文献
12.
Fixed Point Theorems on Chain Complete Partially Ordered Sets 总被引:1,自引:0,他引:1
In this paper, we extend the results of Tarski, Abian and Brown on the completeness of lattices by fixed point theorems, to partially ordered sets or (Po sets) with chain completeness property. We also sharpen some of the existing results on completeness of lattices and fixed-point theorems. We also provide counter examples to some of the claims of R. Taskovic to disprove his theorem.Milan R. Taskovic claims to have proved this theorem but his proof is based on a false argument. In fact most of the contentions of Milan R. Taskovic in [4] are factually incorrect. Actually, reviewer of Taskovics paper has pointed out some of his inaccurate observations. See Mathematical Reviews No. 90b:06007, 06A10. 相似文献
13.
We introduce two numerical invariants of orders that measure how close a poset is to having the fixed point property. We give general properties of those invariants and link them to known results on the fixed point property. 相似文献
14.
研究了平均非扩张型映射T:‖Tx-Ty‖≤a‖x-y‖+b‖x-Tx‖+c‖x-Ty‖,(x,y∈K,a,b,c≥0,a+b+c≤1)的公共不动点的存在性和唯一性.得到平均非扩张型映射T1和T2满足T1T2=T2T1,则T1T2存在唯一的不动点,并且T1和T2存在唯一的公共不动点.本文结果是近期相关文献结果的推广. 相似文献
15.
Piotr Minc 《Transactions of the American Mathematical Society》1999,351(3):1109-1121
An example of a fixed points free map is constructed on a tree-like, weakly chainable continuum.
16.
A. A. Tolstonogov 《Set-Valued Analysis》1998,6(2):129-147
Existence theorems of continuous selectors whose values are fixed points of multivalued contractions are proved. As an application, the existence of continuous selectors to generalized solution sets of partial differential inclusions, depending on a parameter, is obtained. 相似文献
17.
We prove that a primitive substitution Delone set, which is pure point diffractive, is a Meyer set. This answers a question
of J.C. Lagarias. We also show that for primitive substitution Delone sets, being a Meyer set is equivalent to having a relatively
dense set of Bragg peaks. The proof is based on tiling dynamical systems and the connection between the diffraction and dynamical
spectra.
The first author acknowledges support from the NSERC post-doctoral fellowship and thanks the University of Washington and
the University of Victoria for being the host universities of the fellowship. The second author is grateful to the Weizmann
Institute of Science where he was a Rosi and Max Varon Visiting Professor when this work was completed. He was also supported
in part by NSF Grant DMS 0355187. 相似文献
18.
Jonathan David Farley 《Order》1997,14(2):125-143
The fixed point property for finite posets of width 3 and 4 is studied in terms of forbidden retracts. The ranked forbidden retracts for width 3 and 4 are determined explicitly. The ranked forbidden retracts for the width 3 case that are linearly indecomposable are examined to see which are minimal automorphic. Part of a problem of Niederle from 1989 is thus solved. 相似文献
19.
In this paper,we are mainly devoted to solving fixed point problems in more general nonconvex sets via an interior point homotopy method.Under suitable conditions,a constructive proof is given to prove the existence of fixed points,which can lead to an implementable globally convergent algorithm. 相似文献
20.
Mostafa Bachar 《Numerical Functional Analysis & Optimization》2016,37(3):277-283
In this work, we discuss the properties of the common fixed points set of a commuting family of monotone nonexpansive mappings. In particular, we show that under suitable assumptions, this set is a monotone nonexpansive retract. 相似文献