Fuzzy Galois connections on fuzzy posets

The concept of fuzzy Galois connections is defined on fuzzy posets with Bělohlávek's fuzzy Galois connections as a special case. The properties of fuzzy Galois connections are investigated. Then the relations between fuzzy Galois connections and fuzzy closure operators, fuzzy interior operators are studied. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

How to fuzzify a closure space

It is shown here how the Galois connections theory provides a canonical procedure to fuzzify a crisp closure space. Roughly speaking, if S is a space equipped with an ∩-closed set of subsets (the closed subsets), the closed fuzzy subsets of S are the Galois connections between and the valuation set. The closed crisp subsets are particular closed fuzzy subsets.     

Fuzzy closure systems on L—ordered sets

In this paper, notions of fuzzy closure system and fuzzy closure L —system on L —ordered sets are introduced from the fuzzy point of view. We first explore the fundamental properties of fuzzy closure systems. Then the correspondence between fuzzy closure systems (fuzzy closure L —systems) and fuzzy closure operators is established. Finally, we study the connections between fuzzy closure systems and fuzzy Galois connections. © 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim     

Fuzzy Galois connections categorically

This paper presents a systematic investigation of fuzzy (non‐commutative) Galois connections in the sense of R. Bělohlávek [1], from the point of view of enriched category theory. The results obtained show that the theory of enriched categories makes it possible to present the theory of fuzzy Galois connections in a succinct way; and more importantly, it provides a useful method to express and to study the link and the difference between the commutative and the non‐commutative worlds (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Lattices of Fixed Points of Fuzzy Galois Connections

We give a characterization of the fixed points and of the lattices of fixed points of fuzzy Galois connections. It is shown that fixed points are naturally interpreted as concepts in the sense of traditional logic.     

Relational Galois connections between transitive fuzzy digraphs

Fuzzy-directed graphs are often chosen as the data structure to model and implement solutions to several problems in the applied sciences. Galois connections have also shown to be useful both in theoretical and in practical problems. In this paper, the notion of relational Galois connection is extended to be applied between transitive fuzzy directed graphs. In this framework, the components of the connection are crisp relations satisfying certain reasonable properties given in terms of the so-called full powering.     

Galois connections among fuzzy groups, similarities, distances

Given a set S, we define Galois connections between the lattices of the fuzzy subgroups of transformations in S, the lattice of the similarities in S and the lattice of the distances in S.     

一种基于Galois联络的逻辑及其等价形式

将形式化方法引入到Galois联络的研究当中,提出了一种基于Galois联络的逻辑系统LGC,给出了其等价形式并证明了完备性定理.由于Galois联络与粗糙集及概念格有着紧密的联系,故本文的结果对概念格及粗糙集的形式化研究有一定的启示作用.     

A Link Between Two Connectedness Notions

The composition of two previously introduced Galois connections is used to provide a wider perspective on the Clementino–Tholen connectedness versus separation Galois connection. Moreover, a link between this and Castellini's connectedness–disconnectednes Galois connection is also presented.     

Possibility-theoretic extension of derivation operators in formal concept analysis over fuzzy lattices

Formal concept analysis (FCA) associates a binary relation between a set of objects and a set of properties to a lattice of formal concepts defined through a Galois connection. This relation is called a formal context, and a formal concept is then defined by a pair made of a subset of objects and a subset of properties that are put in mutual correspondence by the connection. Several fuzzy logic approaches have been proposed for inducing fuzzy formal concepts from L-contexts based on antitone L-Galois connections. Besides, a possibility-theoretic reading of FCA which has been recently proposed allows us to consider four derivation powerset operators, namely sufficiency, possibility, necessity and dual sufficiency (rather than one in standard FCA). Classically, fuzzy FCA uses a residuated algebra for maintaining the closure property of the composition of sufficiency operators. In this paper, we enlarge this framework and provide sound minimal requirements of a fuzzy algebra w.r.t. the closure and opening properties of antitone L-Galois connections as well as the closure and opening properties of isotone L-Galois connections. We apply these results to particular compositions of the four derivation operators. We also give some noticeable properties which may be useful for building the corresponding associated lattices.     

用模糊Galois联络对L-模糊粗糙集进行公理化刻画

粗糙集理论是由Pawlak提出的一种表示与处理数据表中信息的形式化工具.作为粗糙集概念的推广,一种基于完备剩余格的L-模糊粗糙集已由Radzikowska与Kerre提出,在本文中,我们第一次借助于L-模糊Galois联络对L-模糊粗糙集进行了公理化刻画.由于L-模糊粗糙集及L-模糊Galois联络均为相应经典情形的推广,故本文的结论对于经典粗糙集来说也是成立的,这就意味着通过Galois联络可将经典粗糙集乃至L-模糊粗糙集的公理化统一起来.     

CONNECTEDNESS AND DISCONNECTEDNESS: A DIFFERENT PERSPECTIVE

Abstract

A factorization of a Galois connection investigated earlier is used to give a definition of a connectedness-disconnectedness Galois connection that is free of the notion of constant morphism. A new notion of N-fixed morphism with respect to a class N of monomorphisms is presented. This is used to characterize the connectedness-disconnectedness Galois connection in the case that N is closed under the formation of pullbacks. Some closedness properties of these Galois connections are investigated.     

Topos中的Galois联络

In this paper, we investigate the Galois connections between two partially ordered objects in an arbitrary elementary topos. Some characterizations of Galois adjunctions which is similar to the classical case are obtained by means of the diagram proof. This shows that the diagram method can be used to reconstruct the classical order theory in an arbitrary elementary topos.     

Galois connections for phylogenetic networks and their polytopes

Journal of Algebraic Combinatorics - We describe Galois connections which arise between two kinds of combinatorial structures, both of which generalize trees with labeled leaves, and then apply...     

Division Algebras, Galois Fields, Quadratic Residues

Intended for mathematical physicists interested in applications of the division algebras to physics, this article highlights some of their more elegant properties with connections to the theories of Galois fields and quadratic residues.     

基于格值逻辑的模糊概念格

从逻辑的角度,将非经典逻辑之一的格值逻辑引入概念格,建立了格值模糊形式背景,通过格结构来刻画对象与属性之间的模糊关系,证明了由蕴涵算子诱导的算子对是伽罗瓦连接,并讨论了相关的一些性质,进而给出了格值模糊概念格的构造算法.格值模糊概念格的建立为模糊性与不可比较性信息的处理提供了可靠的数学工具.     

Regular monoids generated by two galois connections

Consider a Galois connection (α, α) on an ordered setP and a Galois connection (β, β) on the dually ordered set . Arbitrary compositions of these Galois connections form a monoid. In this paper we will examine this monoid. First we prove that it is a regular monoid and then we construct two special Galois connectionsa andb such that every monoid of the above type is a homomorphic image of the monoid generated bya andb, and we give a solution of the word problem of the latter monoid.     

Galois connexion of a fuzzy subset

By their representation theorem, Negoita and Ralescu ‘identify’ a fuzzy set with a family of ordinary sets (levels). Here we ‘identify’ a fuzzy set with a Galois connexion between the boolean of a set and the valuation set. The two representations are closely connected.