Abstract
This paper introduces the concept of single–valued neutrosophic EQ–subalgebras, single–valued neutrosophic EQ–prefilters and single–valued neutrosophic EQ–filters. We study some properties of single–valued neutrosophic EQ–prefilters and show how to construct single–valued neutrosophic EQ–filters. Finally, the relationship between single–valued neutrosophic EQ–filters and EQ–filters are studied.
Introduction
EQ-algebra as an alternative to residuated lattices is a special algebra that was presented for the first time by V. Novák [10, 11]. Its original motivation comes from fuzzy type theory, in which the main connective is fuzzy equality and stems from the equational style of proof in logic [15]. EQ-algebras are intended to become algebras of truth values for fuzzy type theory (FTT) where the main connective is a fuzzy equality. Every EQ–algebra has three operations meet “∧”, multiplication “⊗”, and fuzzy equality “∼” and a unit element, while the implication “→” is derived from fuzzy equality “∼”. This basic structure in fuzzy logic is ordering, represented by ∧–semilattice, with maximal element “1”. Further materials regarding EQ–algebras are available in the literature too [6, 12]. Algebras including EQ-algebras have played an important role in recent years and have had its comprehensive applications in many aspects including dynamical systems and genetic code of biology [2]. From the point of view of logic, the main difference between residuated lattices and EQ–algebras lies in the way the implication operation is obtained. While in residuated lattices it is obtained from (strong) conjunction, in EQ–algebras it is obtained from equivalence. Consequently, the two kinds of algebras differ in several essential points despite their many similar or identical properties.
Filter theory plays an important role in studying various logical algebras. From logical point of view, filters correspond to sets of provable formulae. Filters are very important in the proof of the completeness of various logic algebras. Many researchers have studied the filter theory of various logical algebras[3–5].
Neutrosophy, as a newly born science, is a branch of philosophy that studies the origin, nature and scope of neutralities, as well as their interactions with different ideational spectra. It can be defined as the incidence of the application of a law, an axiom, an idea, a conceptual accredited construction on an unclear, indeterminate phenomenon, contradictory to the purpose of making it intelligible. Neutrosophic set and neutrosophic logic are generalizations of the fuzzy set and respectively fuzzy logic (especially of intuitionistic fuzzy set and respectively intuitionistic fuzzy logic) are tools for publications on advanced studies in neutrosophy. In neutrosophic logic, a proposition has a degree of truth (T), indeterminacy (I) and falsity (F), where T, I, F are standard or non–standard subsets of ]-0, 1+[. In 1995, Smarandache talked for the first time about neutrosophy and in 1999 and 2005 [14] he initiated the theory of neutrosophic set as a new mathematical tool for handling problems involving imprecise, indeterminacy, and inconsistent data. Alkhazaleh et al. generalized the concept of fuzzy soft set to neutrosophic soft set and they gave some applications of this concept in decision making and medical diagnosis [1] and Borumand et al. applied the concept of neutrosophic logic in filters in BE-algebras [13].
Regarding these points, this paper aims to introduce the notation of single–valued neutrosophic EQ–subalgebras and single–valued neutrosophic EQ–filters. We investigate some properties of single–valued neutrosophic EQ–subalgebras and single–valued neutrosophic EQ–filters and prove them. Indeed show that how to construct single–valued neutrosophic EQ–subalgebras and single–valued neutrosophic EQ–filters. We applied the concept of homomorphisms in EQ–algebras and with this regard, new single–valued neutrosophic EQ–subalgebras and single–valued neutrosophic EQ–filters are generated.
Preliminaries
In this section, we recall some definitions and results are indispensable to our research paper.
(E, ∧ , 1) is a commutative idempotent monoid (i.e. ∧–semilattice with top element “1”); (E, ⊗ , 1) is a monoid and ⊗ is isotone w.r.t. “≤” (where x ≤ y is defined as x ∧ y = x); x ∼ x = 1; (reflexivity axiom) ((x ∧ y) ∼ z) ⊗ (t ∼ x) ≤ z ∼ (t ∧ y); (substitution axiom) (x ∼ y) ⊗ (z ∼ t) ≤ (x ∼ z) ∼ (y ∼ t); (congruence axiom) (x ∧ y ∧ z) ∼ x ≤ (x ∧ y) ∼ x; (monotonicity axiom) x ⊗ y ≤ x ∼ y, (boundedness axiom).
The binary operation “∧” is called meet (infimum), “⊗” is called multiplication and “∼” is called fuzzy equality. (E, ∧ , ⊗ , ∼ , 1) is called a separated EQ–algebra if 1 = x ∼ y, implies that x = y.
x ⊗ y ≤ x, y, x ⊗ y ≤ x ∧ y; x ∼ y = y ∼ x; (x ∧ y) ∼ x ≤ (x ∧ y ∧ z) ∼ (x ∧ z); x → x = 1; (x ∼ y) ⊗ (y ∼ z) ≤ x ∼ z; (x → y) ⊗ (y → z) ≤ x → z;
(z → (x ∧ y)) ⊗ (x ∼ t) ≤ z → (t ∧ y); (y → z) ⊗ (x → y) ≤ x → z; (x → y) ⊗ (y → x) ≤ x ∼ y; if x ≤ y → z, then if x ≤ y ≤ z, then z ∼ x ≤ z ∼ y and x ∼ z ≤ x ∼ y; x → (y → x) =1.
1 ∈ F, if a, a → b ∈ F, then b ∈ F, if a → b ∈ F, then a ⊗ c → b ⊗ c ∈ F and c ⊗ a → c ⊗ b ∈ F.
if a ∈ F and a ≤ b, then b∈ F ; if a, a ∼ b ∈ F, then b ∈ F; If a, b ∈ F, then a ∧ b ∈ F; If a ∼ b ∈ F and b ∼ c ∈ F then a ∼ c ∈ F.
ν (1) ≥ ν (x); ν (y) ≥ ν ((x ∧ y) ∼ y) ∧ ν (x).
A fuzzy EQ–prefilter is called a fuzzy EQ–filter if it satisfies:
ν ((x ∧ y) ∼ y) ≤ ν ((x ⊗ z) ∧ (y ⊗ z)) ∼ (y ⊗ z)).
Single–Valued Neutrosophic EQ–subalgebras
In this section, we introduce the concept of single–valued neutrosophic EQ–subalgebra and prove some their properties.
T
A
(x ∧ y) = T
A
(x) ∧ T
A
(y) , I
A
(x ∧ y) = I
A
(x) ∧ I
A
(y) and F
A
(x ∧ y) = F
A
(x) ∨ F
A
(y) , T
A
(x ∼ y) ≥ T
A
(x) ∧ T
A
(y) , I
A
(x ∼ y) ≥ I
A
(x) ∧ I
A
(y) and F
A
(x ∼ y) ≤ F
A
(x) ∨ F
A
(y) .
From now on, when we say
if x ≤ y, then T
A
(x) ≤ T
A
(y), if x ≤ y, then I
A
(x) ≤ I
A
(y) , if x ≤ y, then F
A
(x) ≥ F
A
(y), T
A
(x) ≤ T
A
(1) , I
A
(x) ≤ I
A
(1) and F
A
(x) ≥ F
A
(1), T
A
(x ⊗ y) ≤ T
A
(x) ∧ T
A
(y), I
A
(x ⊗ y) ≤ I
A
(x) ∧ T
A
(y), F
A
(x ⊗ y) ≥ F
A
(x) ∨ F
A
(y), T
A
(x → y) ≥ T
A
(x) ∧ T
A
(y), I
A
(x → y) ≥ I
A
(x) ∧ I
A
(y), F
A
(x → y) ≤ F
A
(x) ∨ F
A
(y).
(v) , (vi) , (vii) By the previous items, for all x, y ∈ E, x ⊗ y ≤ x ∧ y implies that T A (x ⊗ y) ≤ T A (x) ∧ T A (y), I A (x ⊗ y) ≤ I A (x) ∧ I A (y) and F A (x ⊗ y) ≥ F A (x) ∨ F A (y).
(viii) , (ix) , (x) Since (x ∼ y) ≤ (x → y), by the previous items we get that T A (x → y) ≥ T A (x) ∧ T A (y), I A (x → y) ≥ I A (x) ∧ T A (y) and F A (x → y) ≤ F A (x) ∨ F A (y).
Define a single valued neutrosophic set map A in E as follows:
if x ≤ y, then T
A
(y → x) = T
A
(x ∼ y) , if x ≤ y, then I
A
(y → x) = I
A
(x ∼ y) , if x ≤ y, then F
A
(y → x) = F
A
(x ∼ y) .
Single–Valued Neutrosophic EQ–prefilters
In this section, we introduce the concept of single–valued neutrosophic EQ–prefilters and show how to construct of single–valued neutrosophic EQ–prefilters.
T A (x) ≤ T A (1) , I A (x) ≥ I A (1) and F A (x) ≤ F A (1) ,
∧ {T A (x) , T A (x → y)} ≤ T A (y) , ∨ {I A (x) , I A (x → y)} ≥ I A (y) and ∧ {F A (x) , F A (x → y)} ≤ F A (y).
In the following theorem, we will show that how to construct of single–valued neutrosophic EQ–prefilters in EQ–algebras.
If x ≤ y, then ∧ {T
A
(x) , T
A
(x → y)} = T
A
(x), If x ≤ y, then ∨ {I
A
(x) , I
A
(x → y)} = I
A
(x), If x ≤ y, then ∧ {F
A
(x) , F
A
(x → y)} = F
A
(x), If x ≤ y, then T
A
(x) ≤ T
A
(y) and F
A
(x) ≤ F
A
(y), If x ≤ y, then I
A
(y) ≤ I
A
(x).
∧ {T
A
(0) , T
A
(0 → y)} = T
A
(0), ∨ {I
A
(0) , I
A
(0 → y)} = I
A
(0),
∧ {T
A
(y) , T
A
(y → 1)} = T
A
(y), ∨ {I
A
(y) , I
A
(y → 1)} = I
A
(y), ∧ {T
A
(y) , T
A
(y → y)} = T
A
(y), ∨ {I
A
(y) , I
A
(y → y)} = I
A
(y), T
A
(0) ≤ T
A
(1) and I
A
(1) ≤ I
A
(0), T
A
(x) ≤ T
A
(y → x) and I
A
(x → y) ≥ I
A
(y), T
A
(x ⊗ y) ≤ T
A
(y ∼ x) and I
A
(x ⊗ y) ≥ I
A
(y ∼ x).
∧ {T
A
(x) , T
A
(x ∼ y)} ≤ T
A
(y) and (I
A
(x) ∨ I
A
(x ∼ y)) ≥ I
A
(y), ∧ {T
A
(x) , T
A
(x ⊗ y)} ≤ T
A
(y) and (I
A
(x) ∨ I
A
(x ⊗ y)) ≥ I
A
(y), ∧ {T
A
(x) , T
A
(x ∧ y)} ≤ T
A
(y) and (I
A
(x) ∨ I
A
(x ∧ y)) ≥ I
A
(y), T
A
(x) ∧ T
A
(y) ≤ T
A
(x) ∧ T
A
(x → y), I
A
(x) ∨ I
A
(x → y) ≤ I
A
(x) ∨ I
A
(y), T
A
(x ⊗ y) ≤ T
A
(x) ∧ T
A
(x), I
A
(x ⊗ y) ≥ I
A
(x) ∨ I
A
(x).
∧ {F
A
(x) , F
A
(x ∼ y)} ≤ F
A
(y), ∧ {F
A
(x) , F
A
(x ⊗ y)} ≤ F
A
(y), ∧ {F
A
(x) , F
A
(x ∧ y)} ≤ F
A
(y), F
A
(x) ∧ F
A
(y) ≤ F
A
(x) ∧ F
A
(x → y), F
A
(x ⊗ y) ≤ F
A
(x) ∧ F
A
(x).
If x ≤ y, then T
A
(x) ∧ T
A
(x ∼ y) = T
A
(x) ∧ T
A
(y → x), If x ≤ y, then T
A
(z) ∧ T
A
(z → x) ≤ T
A
(y), If x ≤ y, then T
A
(x) ∧ T
A
(y → z) = T
A
(x) ∧ T
A
(z), If x ≤ y, then I
A
(x) ∨ I
A
(x ∼ y) = I
A
(x) ∨ I
A
(y → x), If x ≤ y, then I
A
(z) ∨ I
A
(z → x) = I
A
(x) ∨ I
A
(z), If x ≤ y, then I
A
(x) ∨ I
A
(y → z) = I
A
(x) ∨ I
A
(z).
If x ≤ y, then F
A
(x) ∧ F
A
(x ∼ y) = F
A
(x) ∧ F
A
(y → x), If x ≤ y, then F
A
(z) ∧ F
A
(z → x) = F
A
(x) ∧ F
A
(z), If x ≤ y, then F
A
(x) ∧ F
A
(y → z) = F
A
(x) ∧ F
A
(z).
T
A
(x ∧ y) = T
A
(x) ∧ T
A
(y), T
A
(x) ∧ T
A
(x ∼ y) ≤ T
A
(x) ∧ T
A
(y),
F
A
(x ∧ y) = F
A
(x) ∧ F
A
(y), F
A
(x) ∧ F
A
(x ∼ y) ≤ F
A
(x) ∧ F
A
(y),
I
A
(x ∧ y) = I
A
(x) ∨ I
A
(y), I
A
(x) ∨ I
A
(x ∼ y) ≥ I
A
(x ∧ y),
(ii) Let x, y ∈ E. Then, I A (x) ∨ I A (x ∼ y) ≥ I A (y). Since x ∼ y = y ∼ x, we obtain I A (x) ∨ I A (x ∼ y) = I A (x) ∨ I A (y ∼ x) ≥ I A (x).
So I A (x) ∨ I A (x ∼ y) ≥ I A (x) ∨ I A (y).□
In Example 3.8, for x = a and y = d, we have I A (x) ∨ I A (x ∼ y) = I A (x ∧ y), while x ≠ y.
Single–Valued Neutrosophic EQ–filters
In this section, we introduce the concept of single–valued neutrosophic EQ–filters as generalization of single–valued neutrosophic EQ–prefilters and prove some their properties.
T
A
(x) ≤ T
A
(1) , I
A
(x) ≥ I
A
(1) and F
A
(x) ≤ F
A
(1) , ∧ {T
A
(x) , T
A
(x → y)} ≤ T
A
(y) , ∨ {I
A
(x) , I
A
(x → y)} ≥ I
A
(y) and ∧ {F
A
(x) , F
A
(x → y)} ≤ F
A
(y), T
A
(x → y) ≤ T
A
((x ⊗ z) → (y ⊗ z)) , I
A
(x → y) ≥ I
A
((x ⊗ z) → (y ⊗ z)) , and F
A
(x → y) ≤ F
A
((x ⊗ z) → (y ⊗ z)).
In the following theorem, we will show that how to construct of single–valued neutrosophic EQ–prefilters in EQ–algebras.
If T
A
(x → y) = T
A
(1), then for every z ∈ E, T
A
((x ⊗ z) → (y ⊗ z)) = T
A
(x → y). If x ≤ y, then for every z ∈ E, T
A
((x ⊗ z) → (y ⊗ z)) = T
A
(x → y). If T
A
(x → y) = T
A
(0), then for every z ∈ E, T
A
((x ⊗ z) → (y ⊗ z)) ≥ T
A
(x → y). If I
A
(x → y) = I
A
(1), then for every z ∈ E, I
A
((x ⊗ z) → (y ⊗ z)) = I
A
(x → y). If x ≤ y, then for every z ∈ E, I
A
((x ⊗ z) → (y ⊗ z)) = I
A
(x → y). If I
A
(x → y) = I
A
(0), then for every z ∈ E, I
A
((x ⊗ z) → (y ⊗ z)) ≤ I
A
(x → y).
(ii) Since x ≤ y we get that x → y = 1 and by definition x ⊗ z ≤ y ⊗ z. Hence by item (i), we have T A ((x ⊗ z) → (y ⊗ z)) = T A (x → y). (v) It is similar to the item (ii) .□
T
A
(0 → y) = T
A
((x ⊗ z) → (y ⊗ z)), T
A
(x → x) = T
A
((x ⊗ z) → (y ⊗ z)), T
A
(x → 1) = T
A
((x ⊗ z) → (y ⊗ z)), I
A
(0 → y) = I
A
((x ⊗ z) → (y ⊗ z)), I
A
(x → x) = I
A
((x ⊗ z) → (y ⊗ z)), I
A
(x → 1) = I
A
((x ⊗ z) → (y ⊗ z)).
If F
A
(x → y) = F
A
(1), then for every z ∈ E, F
A
((x ⊗ z) → (y ⊗ z)) = F
A
(x → y), If x ≤ y, then for every z ∈ E, F
A
((x ⊗ z) → (y ⊗ z)) = F
A
(x → y). If F
A
(x → y) = F
A
(0), then for every z ∈ E, F
A
((x ⊗ z) → (y ⊗ z)) ≥ F
A
(x → y).
T
A
(x ⊗ y) = T
A
(x) ∧ T
A
(y), I
A
(x ⊗ y) = I
A
(x) ∨ I
A
(y), T
A
(x ∼ y) ≤ T
A
(y → x), T
A
(z) ∧ T
A
(y) ≤ T
A
(x → z), T
A
(x ∼ y) ∧ T
A
(y ∼ z) ≤ T
A
(x ∼ z), I
A
(x ∼ y) ≥ I
A
(y → x), I
A
(z) ∨ I
A
(y) ≥ I
A
(x → z), I
A
(x ∼ y) ∨ I
A
(y ∼ z) ≥ I
A
(x ∼ z).
F (x ⊗ y) = F
A
(x) ∧ F
A
(y), F
A
(x ∼ y) ≤ F
A
(y → x), F
A
(z) ∧ F
A
(y) ≤ F
A
(x → z), F
A
(x ∼ y) ∧ F
A
(y ∼ z) ≤ F
A
(x ∼ z).
Special single–valued neutrosophic EQ–filters
In this section, we apply the concept of homomorphisms and (α, β, γ)–level sets to construct of single–valued neutrosophic EQ–filters.
if ∅ ≠ A(α,β,γ), then A(α,β,γ) is an EQ–filter of if A(α,β,γ) is an EQ–filter of
(ii) ∅ ≠ A(α,β,γ), implies that there exists x ∈ A(α,β,γ). By Theorem 3.6, we conclude that α ≤ T A (x) ≤ T A (1) , β ≤ F A (x) ≤ F A (1) and γ ≥ I A (x) ≥ I A (1). Therefore, 1 ∈ A(α,β,γ).
Let x ∈ A(α,β,γ) and x ≤ y. Since T A and F A are monotone maps and I A is an antimonotone map, we get that α ≤ T A (x) ≤ T A (y) , β ≤ F A (x) ≤ F A (y) and γ ≥ I A (x) ≥ I A (y). Hence y ∈ A(α,β,γ).
Let x ∈ A(α,β,γ) and x → y ∈ A(α,β,γ). Since A is a single–valued neutrosophic EQ–filter of
Let x → y ∈ A(α,β,γ) and z ∈ E. Since A is a single–valued neutrosophic EQ–filter of
(iii)
Let x, y, z ∈ E. Consider α
x
= T
A
(x) , β
x
= F
A
(x) and γ
x
= I
A
(x) . Since A(α,β,γ) is an EQ–filter of
Let αx→y = T
A
(x → y) , βx→y = F
A
(x → y), γx→y = I
A
(x → y), α = α
x
∧ αx→y, β = β
x
∧ βx→y and γ = γ
x
∨ γx→y . We have T
A
(x) = α
x
≥ α, T
A
(x → y) = αx→y ≥ α, F
A
(x) = β
x
≥ β, F
A
(x → y) = βx→y ≥ β and I
A
(x) = γ
x
≤ γ, I
A
(x → y) = γx→y ≤ γ, so x, x → y ∈ A(α,β,γ). Since A(α,β,γ) is an EQ–filter of
A(α,β,γ) is an EQ–filter of If G
A
= {x ∈ E | T
A
(1) = F
A
(1) =1, I
A
(0) =1}, then G
A
is an EQ–filter in
Let A = (T
A
, F
A
, I
A
) be a single–valued neutrosophic EQ–filter in
Then we have the following corollary.
A is a normal single–valued neutrosophic EQ–filter of If there exists a sequence
Let A = (T
A
, I
A
, F
A
) be a single–valued neutrosophic EQ–filter of
(ii) Let x ∈ E. Since I
A
(x) ≤ I
A
(0) we get that
(iii) Assume that x ∈ E. Then
Then
Define a single valued neutrosophic set map A in E as follows:
(A+p) +p = A+p if and only if p = 1, (A+p) +p = A if and only if A is a normal single–valued neutrosophic EQ–filter.
Let A = (T
A
, I
A
, F
A
) be a single–valued neutrosophic EQ–filter of
if x ≤ y, then A
g
is a single–valued neutrosophic EQ–filter of
Let z ∈ E. Since g (x ⊗ z → y ⊗ z) = g (x ⊗ z) → g (y ⊗ z), we get that
Then
Hence
and
Conclusion
The current paper considered the concept of single–valued neutrosophic EQ–algebras and introduce the concepts single–valued neutrosophic EQ–subalgebras, single–valued neutrosophic EQ–prefilters and single–valued neutrosophic EQ–filters. It is showed that single–valued neutrosophic EQ–subalgebras preserve some binary relation on EQ–algebras under some conditions. Using the some properties of single–valued neutrosophic EQ–prefilters, we construct new single–valued neutrosophic EQ–prefilters. We considered that single–valued neutrosophic EQ–filters as generalisation of single–valued neutrosophic EQ–prefilters and constructed them. We connected the concept of EQ–prefilters to single–valued neutrosophic EQ–prefilters and the concept of EQ–filters to single–valued neutrosophic EQ–filters, so we obtained such structures from this connection.
Footnotes
Acknowledgments
The authors would like to express their gratitude to anonymous referees for their comments and suggestions which improved the paper.
