scholarly journals Bipolar Fuzzy Relations

Mathematics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 1044 ◽  
Author(s):  
Jeong-Gon Lee ◽  
Kul Hur

We introduce the concepts of a bipolar fuzzy reflexive, symmetric, and transitive relation. We study bipolar fuzzy analogues of many results concerning relationships between ordinary reflexive, symmetric, and transitive relations. Next, we define the concepts of a bipolar fuzzy equivalence class and a bipolar fuzzy partition, and we prove that the set of all bipolar fuzzy equivalence classes is a bipolar fuzzy partition and that the bipolar fuzzy equivalence relation is induced by a bipolar fuzzy partition. Finally, we define an ( a , b ) -level set of a bipolar fuzzy relation and investigate some relationships between bipolar fuzzy relations and their ( a , b ) -level sets.

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Madad Khan ◽  
Muhammad Zeeshan ◽  
Seok-Zun Song ◽  
Sohail Iqbal

In this paper, we introduce types of relations on complex fuzzy sets such as the complex fuzzy (CF) inverse relation, complex fuzzy reflexive relation, complex fuzzy symmetric relation, complex fuzzy antisymmetric relation, complex fuzzy transitive relation, complex fuzzy irreflexive relation, complex fuzzy asymmetric relation, complex fuzzy equivalence relation, and complex fuzzy-order relation. We study some basic results and particular examples of these relations. Moreover, we discuss the applications of complex fuzzy relations in Future Commission Market (FCM). We show that the introduction of CF relations to applications of FCMs can give a significant method for describing the temporal dependence between parameters of a Future Commission Market.


2003 ◽  
Vol 13 (07) ◽  
pp. 1911-1915 ◽  
Author(s):  
Z. Leśniak

We consider an equivalence relation for a given free mapping f of the plane. Under the assumption that f is embeddable in a flow {ft : t ∈ R} we describe the structure of equivalence classes of the relation. Finally, we prove that f restricted to each equivalence class is a Sperner homeomorphism.


1983 ◽  
Vol 48 (3) ◽  
pp. 542-557 ◽  
Author(s):  
Matatyahu Rubin ◽  
Saharon Shelah

AbstractWe prove that the logics of Magidor-Malitz and their generalization by Rubin are distinct even for PC classes.Let M ⊨ Qnx1 … xnφ(x1 … xn) mean that there is an uncountable subset A of ∣M∣ such that for every a1 …, an ∈ A, M ⊨ φ[a1, …, an].Theorem 1.1 (Shelah) (♢ℵ1). For every n ∈ ωthe classKn+1 = {‹A, R› ∣ ‹A, R› ⊨ ¬ Qn+1x1 … xn+1R(x1, …, xn+1)} is not an ℵ0-PC-class in the logic ℒn, obtained by closing first order logic underQ1, …, Qn. I.e. for no countable ℒn-theory T, isKn+1the class of reducts of the models of T.Theorem 1.2 (Rubin) (♢ℵ1). Let M ⊨ QE x yφ(x, y) mean that there is A ⊆ ∣M∣ such thatEA, φ = {‹a, b› ∣ a, b ∈ A and M ⊨ φ[a, b]) is an equivalence relation on A with uncountably many equivalence classes, and such that each equivalence class is uncountable. Let KE = {‹A, R› ∣ ‹A, R› ⊨ ¬ QExyR(x, y)}. Then KE is not an ℵ0-PC-class in the logic gotten by closing first order logic under the set of quantifiers {Qn ∣ n ∈ ω) which were defined in Theorem 1.1.


1990 ◽  
Vol 10 (1) ◽  
pp. 1-14 ◽  
Author(s):  
Scot Adams

AbstractLet R be a Borel equivalence relation with countable equivalence classes on a measure space M. Intuitively, a ‘treeing’ of R is a measurably-varying way of makin each equivalence class into the vertices of a tree. We make this definition rigorous. We prove that if each equivalence class becomes a tree with polynomial growth, then the equivalence relation is amenable. We prove that if the equivalence relation is finite measure-preserving and amenable, then almost every tree (i.e., equivalence class) must have one or two ends.


2012 ◽  
Vol 77 (4) ◽  
pp. 1165-1183
Author(s):  
James H. Schmerl

AbstractA structure is an n-grid if each Ei, is an equivalence relation on A and whenever X and Y are equivalence classes of, respectively, distinct Ei, and Ej, then X ∩ Y is finite. A coloring χ: A → n is acceptable if whenever X is an equivalence class of Ei, then {x ∈ X: χ(x) = i} is finite. If B is any set, then the n-cube Bn = (Bn; E0, …, En−1) is considered as an n-grid, where the equivalence classes of Ei are the lines parallel to the i-th coordinate axis. Kuratowski [9], generalizing the n = 3 case proved by Sierpihski [17], proved that ℝn has an acceptable coloring iff 2ℵ0 ≤ ℵn−2. The main result is: if is a semialgebraic (i.e., first-order definable in the field of reals) n-grid, then the following are equivalent: (1) if embeds all finite n-cubes, then 2ℵ0 ≤ ℵn−2: (2) if embeds ℝn, then 2ℵ0 ≤ ℵn−2; (3) has an acceptable coloring.


1997 ◽  
Vol 62 (2) ◽  
pp. 337-365 ◽  
Author(s):  
Greg Hjorth

AbstractThe Martin-Steel coarse inner model theory is employed in obtaining new results in descriptive set theory. determinacy implies that for every thin equivalence relation there is a real, N, over which every equivalence class is generic—and hence there is a good (N#) wellordering of the equivalence classes. Analogous results are obtained for and quasilinear orderings and determinacy is shown to imply that every prewellorder has rank less than .


2021 ◽  
Vol 0 (0) ◽  
pp. 0
Author(s):  
Dirk Frettlöh ◽  
Alexey Garber ◽  
Lorenzo Sadun

<p style='text-indent:20px;'>Two Delone sets are bounded distance equivalent to each other if there is a bijection between them such that the distance of corresponding points is uniformly bounded. Bounded distance equivalence is an equivalence relation. We show that the hull of a repetitive Delone set with finite local complexity has either one equivalence class or uncountably many.</p>


1999 ◽  
Vol 64 (4) ◽  
pp. 1403-1406 ◽  
Author(s):  
Todd Hammond

Let {We}e∈ω be a standard enumeration of the recursively enumerable (r.e.) subsets of ω = {0,1,2,…}. The lattice of recursively enumerable sets, , is the structure ({We}e∈ω,∪,∩). ≡ is a congruence relation on if ≡ is an equivalence relation on and if for all U, U′ ∈ and V, V′ ∈ , if U ≡ U′ and V ≡ V′, then U ∪ V ≡ U′ ∪ V′ and U ∩ V ≡ U′ ∩ V′. [U] = {V ∈ | V ≡ U} is the equivalence class of U. If ≡ is a congruence relation on , the elements of the quotient lattice / ≡ are the equivalence classes of ≡. [U] ∪ [V] is defined as [U ∪ V], and [U] ∩ [V] is defined as [U ∩ V]. We say that a congruence relation ≡ on is if {(i, j)| Wi ≡ Wj} is . Define =* by putting Wi, =* Wj if and only if (Wi − Wj)∪ (Wj − Wi) is finite. Then =* is a congruence relation. If D is any set, then we can define a congruence relation by putting Wi Wj if and only if Wi ∩ D =* Wj ∩D. By Hammond [2], a congruence relation ≡ ⊇ =* is if and only if ≡ is equal to for some set D.The Friedberg splitting theorem [1] asserts that if A is any recursively enumerable set, then there exist disjoint recursively enumerable sets A0 and A1 such that A = A0∪ A1 and such that for any recursively enumerable set B


2002 ◽  
Vol 67 (2) ◽  
pp. 497-504
Author(s):  
Todd Hammond

Let {We}e∈ω be a standard enumeration of the recursively enumerable (r. e.) subsets of ω = {0, 1, 2, …}. The lattice of recursively enumerable sets, is the structure ({We}e∈ω, ∪, ∩). is the sublattice of consisting of the recursive sets.Suppose is a lattice of subsets of ω. ≡ is said to be a congruence relation on if ≡ is an equivalence relation on and if for all U, U′ ∈ and V, V ∈ , if U ≡ U′ and V ≡ V′ then U ∪ U′ ≡ V ∪ V′ and U ∩ U′ ≡ V ∩ V′. [U] = {V ∈ | V ≡ U} is the equivalence class of U. If ≡ is a congruence relation on , the elements of the quotient lattice / ≡ are the equivalence classes of ≡. [U] ∪ [V] is defined as [U ∪ V], and [U] ∩ [V] is defined as [U ∩ V].The quotient lattices of (or of some sublattice ) correspond naturally with the congruence relations which give rise to them, and in turn the congruence relations of sublattices of can be characterized in part by their computational complexity. The aim of the present paper is to characterize congruence relations in some of the most important complexity classes.


Mathematics ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 1441
Author(s):  
Juan-De-Dios González-Hedström ◽  
Juan-José Miñana ◽  
Oscar Valero

Indistinguishability fuzzy relations were introduced with the aim of providing a fuzzy notion of equivalence relation. Many works have explored their relation to metrics, since they can be interpreted as a kind of measure of similarity and this is, in fact, a dual notion to dissimilarity. Moreover, the problem of how to construct new indistinguishability fuzzy relations by means of aggregation has been explored in the literature. In this paper, we provide new characterizations of those functions that allow us to merge a collection of indistinguishability fuzzy relations into a new one in terms of triangular triplets and, in addition, we explore the relationship between such functions and those that aggregate extended pseudo-metrics, which are the natural distances associated to indistinguishability fuzzy relations. Our new results extend some already known characterizations which involve only bounded pseudo-metrics. In addition, we provide a completely new description of those indistinguishability fuzzy relations that separate points, and we show that both differ a lot.


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