Fuzzy Galois Connections Research Articles

Fuzzy Galois connections in L-fuzzy posets

We consider properties of fuzzy Galois connections on L-fuzzy posets for complete residuated lattices L and show some results about their properties by operator-based methods. We also prove that there is a new fuzzy Galois connection on fuzzy posets. Moreover, we give a simple condition for the existence of right adjoint map.

Fuzzy closure structures as formal concepts

Galois connections seem to be ubiquitous in mathematics. They have been used to model solutions for both pure and application-oriented problems. Throughout the paper, the general framework is a complete fuzzy lattice over a complete residuated lattice. The existence of three fuzzy Galois connections (two antitone and one isotone) between three specific ordered sets is proved in this paper. The most interesting part is that fuzzy closure systems, fuzzy closure operators and strong fuzzy closure relations are formal concepts of these fuzzy Galois connections.

Fuzzy Galois connections on Alexandrov L-topologies

In this paper, we introduce the notion of Galois and dual Galois connections as a topological viewpoint of concept lattices in a complete residuated lattice. Under various relations, we investigate the Galois and dual Galois connections on Alexandrov L-topologies. Moreover, their properties and examples are investigated.

Fuzzy Galois connections on fuzzy sets

In fairly elementary terms this paper presents how the theory of preordered fuzzy sets, more precisely quantale-valued preorders on quantale-valued fuzzy sets, is established under the guidance of enriched category theory. Motivated by several key results from the theory of quantaloid-enriched categories, this paper develops all needed ingredients purely in order-theoretic languages for the readership of fuzzy set theorists, with particular attention paid to fuzzy Galois connections between preordered fuzzy sets.

Triadic fuzzy Galois connections as ordinary connections

We present results on triadic Galois connections and trilattices associated with ternary fuzzy relations. These structures are fundamental in the analysis of three-way relational data. We provide an axiomatization of triadic fuzzy Galois connections and establish two ways of representing these structures by their ordinary counterparts—one via a Cartesian representation and the other via a-cuts. The results allow us to easily transfer some of the known results from the ordinary case to the fuzzy case. This transfer is illustrated by an alternative proof of the basic theorem of fuzzy concept trilattices via reduction to the ordinary basic theorem. In addition, we provide a hint to generalize the presented results to n-ary structures which are of increasing importance in data analysis of n-way data.

Fuzzy Connections and Relations in Complete Residuated Lattices

In this paper, we investigate the properties of fuzzy Galois (dual Galois, residuated, and dual residuated) connections in a complete residuated lattice L. We give their examples. In particular, we study fuzzy Galois (dual Galois, residuated, dual residuated) connections induced by L-fuzzy relations.

FUZZY CONNECTIONS AND COMPLETENESS IN COMPLETE RESIDUATED LATTICES

In this paper, we investigate the properties of fuzzy Galois (dual Galois, residuated, dual residuated) connections in a complete residuated lattice $L$.

Fuzzy Bases of Fuzzy Domains

This paper is an attempt to develop quantitative domain theory over frames. Firstly, we propose the notion of a fuzzy basis, and several equivalent characterizations of fuzzy bases are obtained. Furthermore, the concept of a fuzzy algebraic domain is introduced, and a relationship between fuzzy algebraic domains and fuzzy domains is discussed from the viewpoint of fuzzy basis. We finally give an application of fuzzy bases, where the image of a fuzzy domain can be preserved under some special kinds of fuzzy Galois connections.

Fuzzy closure systems onL-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 under weak conditions

Operators that allow to transport L-sets along binary L-relations are considered, assuming L to be a quite general lattice-ordered algebra. Functoriality conditions and fuzzy Galois connections involving these operators, already known for a complete residuated lattice L, are investigated in case of complete distributive extended-order algebras that need not be commutative or associative.

Isotone fuzzy Galois connections with hedges

We study isotone fuzzy Galois connections and concept lattices parameterized by particular unary operators. The operators represent linguistic hedges such as “very”, “rather”, “more or less”, etc. Isotone fuzzy Galois connections and concept lattices provide an alternative to their antitone counterparts which are the fundamental structures behind formal concept analysis of data with fuzzy attributes. We show that hedges enable us to control the number of formal concepts in the associated concept lattice. We also describe the structure of the concept lattice and provide a counterpoint to the main theorem of concept lattices.

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)

Interval-Valued Fuzzy Galois Connections: Algebraic Requirements and Concept Lattice Construction

Fuzzy formal concept analysis is concernedwith formal contexts expressing scalar-valued fuzzy relationships between objects and their properties. Existing fuzzy approaches assume that the relationship between given and given property is matter of degree in scale L (generally [0,1]). However, the extent to which object o has property a may be sometimes hard to assess precisely. Then it is convenient to use sub-interval from the scale L rather than precise value. Such formal contexts naturally lead to interval-valued fuzzy formal concepts. The aim of the paper is twofold. We provide sound minimal set of algebraic requirements for interval-valued implications in order to fulfill the fuzzy closure properties of the resulting Galois connection. Secondly, new approach based on generalization of Godel implication is proposed for building the complete lattice of all interval-valued fuzzy formal concepts.

Quantitative domains via fuzzy sets: Part I: Continuity of fuzzy directed complete posets

This paper deals with quantitative domain theory via fuzzy sets. It examines the continuity of fuzzy directed complete posets (dcpos for short) based on complete residuated lattices. First, we show that a fuzzy partial order in the sense of Fan and Zhang and an L-order in the sense of Bělohlávek are equivalent to each other. Then we redefine the concepts of fuzzy directed subsets and (continuous) fuzzy dcpos. We also define and study fuzzy Galois connections on fuzzy posets. We investigate some properties of (continuous) fuzzy dcpos. We show that a fuzzy dcpo is continuous if and only if the fuzzy-double-downward-arrow-operator has a right adjoint. We define fuzzy auxiliary relations on fuzzy posets and approximating fuzzy auxiliary relations on fuzzy dcpos. We show that a fuzzy dcpo is continuous if and only if the fuzzy way-below relation is the smallest approximating fuzzy auxiliary relation.

Fuzzy Galois connections on fuzzy posets

AbstractThe 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)

A note on variable threshold concept lattices: Threshold-based operators are reducible to classical concept-forming operators

The present paper deals with formal concept analysis of data with fuzzy attributes. We clarify several points of a new approach of [S.Q. Fan, W.X. Zhang, Variable threshold concept lattice, Inf. Sci., accepted for publication] which is based on using thresholds in concept-forming operators. We show that the extent- and intent-forming operators from [S.Q. Fan, W.X. Zhang, Inf. Sci., accepted for publication] can be defined in terms of basic fuzzy set operations and the original operators as introduced and studied e.g. in [R. Belohlavek, Fuzzy Galois connections, Math. Logic Quarterly 45 (4) (1999) 497–504; R. Belohlavek, Concept lattices and order in fuzzy logic, Ann. Pure Appl. Logic 128 (2004) 277–298; S. Pollandt, Fuzzy Begriffe, Springer-Verlag, Berlin/Heidelberg, 1997]. As a consequence, main properties of the new operators from [S.Q. Fan, W.X. Zhang, Inf. Sci., accepted for publication], including the properties studied in [S.Q. Fan, W.X. Zhang, Inf. Sci., accepted for publication], can be obtained as consequences of the original operators from [R. Belohlavek, 1999; R. Belohlavek, 2004; S. Pollandt, 1997].

Non-commutative fuzzy Galois connections

Fuzzy Galois connections were introduced by Bělohlavek in [4]. The structure considered there for the set of truth values is a complete residuated lattice, which places the discussion in a “commutative fuzzy world”. What we are doing in this paper is dropping down the commutativity, getting the corresponding notion of Galois connection and generalizing some results obtained by Bělohlavek in [4] and [7]. The lack of the commutative law in the structure of truth values makes it appropriate for dealing with a sentences conjunction where the order between the terms of the conjunction counts, gaining thus a temporal dimension for the statements. In this “non-commutative world”, we have not one, but two implications ([15]). As a consequence, a Galois connection will not be a pair, but a quadruple of functions, which is in fact two pairs of functions, each function being in a symmetric situation to his pair. Stating that these two pairs are compatible in some sense, we get the notion of strong L-Galois connection, a more operative and prolific notion, repairing the “damage” done by non-commutativity.

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.

Fuzzy Galois Connections

AbstractThe concept of Galois connection between power sets is generalized from the point of view of fuzzy logic. Studied is the case where the structure of truth values forms a complete residuated lattice. It is proved that fuzzy Galois connections are in one‐to‐one correspondence with binary fuzzy relations. A representation of fuzzy Galois connections by (classical) Galois connections is provided.