1. Introduction
The concept of a ring first arose from attempts to prove Fermat’s last theorem [
1], starting with Richard Dedekind in the 1880s. After contributions from other fields, mainly number theory, the notion of a ring was generalized and firmly established during the 1920s by Emmy Noether and Wolfgang Krull [
2]. Modern ring theory, a very active mathematical discipline, studies rings in their own right. To explore rings, mathematicians have devised various notions to break rings into smaller, more understandable pieces, such as ideals, quotient rings, and simple rings. In addition to these abstract properties, ring theorists also make various distinctions between the theories of commutative rings and noncommutative rings, the former belonging to algebraic number theory and algebraic geometry. A particularly rich theory has been developed for a certain special class of commutative rings, known as fields, which lies within the realm of field theory. Likewise, the corresponding theory for noncommutative rings, that of noncommutative division rings, constitutes an active research interest for noncommutative ring theorists. Since the discovery of a mysterious connection between noncommutative ring theory and geometry during the 1980s by Alain Connes [
3,
4,
5], noncommutative geometry has become a particularly active discipline in ring theory.
The foundation of the subject (i.e., the mapping from subfields to subgroups and vice versa) is set up in the context of an absolutely general pair of fields. In addition to the clarification that normally accompanies such a generalization, there are useful applications to infinite algebraic extensions and to the Galois Theory of differential equations [
6]. There is also a logical simplicity to the procedure: everything hinges on a pair of estimates of field degrees and subgroup indices. One might describe it as a further step in the Dedekind–Artin linearization [
7].
An early contributor to the theory of noncommutative rings was the Scottish mathematician Wedderburn who, in 1905, proved “Wedderburn’s Theorem”, namely that every finite division ring is commutative and so is a field [
8]. It was only around the 1930s that the theories of commutative and noncommutative rings came together and that their ideas began to influence each other.
Neutrosophy is a new branch of philosophy which studies the nature, origin, and scope of neutralities as well as their interaction with ideational spectra. The concept of neutrosophic logic and a neutrosophic set was first introduced by Florentin Smarandache [
9] in 1995, where each proposition in neutrosophic logic is approximated to have the percentage of truth in a subset T, the percentage of indeterminacy in a subset I, and the percentage of falsity in a subset F such that this neutrosophic logic is called an extension of fuzzy logic, especially to intuitionistic fuzzy logic [
10]. The generalization of classical sets [
9], fuzzy sets [
11], and intuitionistic fuzzy sets [
10], etc., is in fact the neutrosophic set. This mathematical tool is used to handle problems consisting of uncertainty, imprecision, indeterminacy, inconsistency, incompleteness, and falsity. By utilizing the idea of neutrosophic theory, Vasantha Kandasamy and Florentin Smarandache studied neutrosophic algebraic structures [
12,
13,
14] by inserting a literal indeterminate element ‘‘I’’, where I
2 = I, in the algebraic structure and then combining ‘‘I’’ with each element of the structure with respect to the corresponding binary operation, denoted *. They call it the neutrosophic indeterminate element, and the generated algebraic structure is then termed as a neutrosophic algebraic structure. Some other neutrosophic algebraic structures can be seen as neutrosophic fields [
15], neutrosophic vector spaces [
16], neutrosophic groups [
17], neutrosophic bigroups [
17], neutrosophic N-groups [
15], neutrosophic semigroups [
12], neutrosophic bisemigroups [
12], neutrosophic N-semigroups [
12], neutrosophic loops [
12], neutrosophic biloops [
12], neutrosophic N-loop [
12], neutrosophic groupoids [
12] and neutrosophic bigroupoids [
12] and so on.
In this paper, we introduce the neutrosophic triplet ring. Further, we define the neutrosophic triplet zero divisor, neutrosophic triplet subring, neutrosophic triplet ideal, nilpotent neutrosophic triplet, integral neutrosophic triplet domain, and neutrosophic triplet ring homomorphism. Finally, we introduce a neutrosophic triplet field. The rest of the paper is organized as follows. After the literature review in
Section 1 and basic concepts in
Section 2, we introduce the neutrosophic triplet ring in
Section 3.
Section 4 is about the introduction of the integral neutrosophic triplet domain with some of its interesting properties, and is also where we develop the neutrosophic triplet ring homomorphism. In
Section 5, we study neutrosophic triplet fields. Conclusions are given in
Section 6.
2. Basic Concepts
In this section, all definitions and examples have been taken from [
18] to provide some basic concepts about neutrosophic triplets and neutrosophic triplet groups.
Definition 1. Let be a set together with a binary operation . Then is called a neutrosophic triplet set if for any , there exists a neutral of “” called , different from the classical algebraic unitary element, and an opposite of “ ” called , with and belonging to , such that
The element
,
, and
are collectively called a neutrosophic triplet and we denote it by
. By
, we mean the neutral of
, and
is just the first coordinate of a neutrosophic triplet and not a neutrosophic triplet [
18].
For the same element “a” in N, there may be more than one neutral neut(a) and more than one opposite .
Definition 2. The element in is the second component, denoted by , of a neutrosophic triplet, if there exist other elements and in such that and . The formed neutrosophic triplet is [12]. Definition 3. The element in is the third component, denoted by of a neutrosophic triplet, if there exist other elements and in such that and . The formed neutrosophic triplet is [12]. Definition 4. Let be a neutrosophic triplet set. Then is called a neutrosophic triplet group if the following conditions are satisfied [18]. - 1.
If is well defined, i.e., for any , one has .
- 2.
If is associative, i.e., for all .
The neutrosophic triplet group, in general, is not a group in the classical algebraic sense. We consider the neutrosophic neutrals as replacing the classical unitary element, and the neutrosophic opposites as replacing the classical inverse elements.
Example 1. Consider under multiplication modulo , where . Then the element gives rise to a neutrosophic triplet because , as . Also, because . Thus is a neutrosophic triplet. Similarly gives rise to a neutrosophic triplet because . So is a neutrosophic triplet. Also, 3 gives rise to the neutrosophic triplet (3, 3, 3). However, has two neutrals: neut(3) = {3, 5}, but 3 does not give rise to a neutrosophic triplet for , since does not exist in with respect to neut(3) = 5. And lastly, gives rise to a zero neutrosophic triplet as . The zero neutrosophic triplet is denoted by .
The classical unitary element of , with respect to multiplication modulo 6, is 1. The neutrosophic triplets on are: (0, 0, 0), (0, 0, 2), (0, 0, 3), (0, 0, 4), (2, 4, 2), (3, 3 3), and (4, 4, 4).
is not a neutrosophic triplet set, since there is no neutrosophic triplet associated to the elements 1 and 5 from , because: there is no neut(1) ≠ 1, and respectively no neut(5) ≠ 1.
But M6 = {0, 2, 3, 4} is a commutative neutrosophic group [18]. Example 2. Consider , where # is defined as .
Let M10 = {0, 2, 4, 5, 6, 8} . Then ( M10, ) is a neutrosophic triplet group under the binary operation as shown in Table 1 [18]. It is also associative, i.e.,
Now we take the LHS to prove the RHS.
The classical unitary element on
with respect to the law
# is
e = 7, since:
Therefore, we choose all triplets whose neutral elements are different from
7, and we get the following neutrosophic triplets:
All above neutrals neut(.) = 0, 2, and 5 are different from the classical unitary element 7.
Z10 is not a neutrosophic triplet group, nor even a neutrosophic triplet set.
But its subset M10 = {0, 2, 4, 5, 6, 8} is a commutative neutrosophic triplet group, since the law # is well-defined, commutative, associative, and each element belonging to M has a corresponding neutrosophic triplet.
3. Neutrosophic Triplet Rings
In this section, we introduce neutrosophic triplet rings and study some of their basic properties and notions.
Definition 5. Let be a set together with two binary operations and . Then is called a neutrosophic triplet ring if the following conditions hold:
- 1.
is a commutative neutrosophic triplet group with respect to ;
- 2.
is well defined and associateve;
- 3.
and for all .
Notations 1. Since the neutrosophic triplet ring and the neutrosophic triplet field are algebraic structures endowed with two internal laws * and #, in order to avoid any confusion, we use the following notation:
neut*(x) and anti*(x) for the neutrals and anti’s, respectively, of the element x with respect to the law * and neu#(x) and ant#(x) for the neutrals and anti’s, respectively, of the element x with respect to the law #.
Remark 1. An NTR in general is not a classical ring.
Definition 6. Let be a neutrosophic triplet ring and let . We call the structure a unitary neutrosophic triplet ring (UNTR) if each element has a neut#(a).
Definition 7. Let be a neutrosophic triplet ring. NTR is called a commutative neutrosophic triplet ring if the law # is commutative.
Definition 8. Let be a neutrosophic triplet ring. If NTR has an element b such that a * b = b * a = b for all a in NTR, then the element b is called the zero neutrosophic element of NTR and denoted by 0.
Hence if NTR has 0 element then 0 * a = a * 0 = 0 for all a in NTR. Also neut*(0) = 0 and anti*(0) = 0.
Notations 2. For neutrosophic triplets with respect to the law * and # are denoted by and respectively.
Definition 9. Let be a neutrosophic triplet ring and let . If there exists a neutrosophic nonzero element such that , then is called a neutrosophic left zero divisor of . Similarly, an element is called a neutrosophic right zero divisor of if .
A neutrosophic zero divisor of an element is one which is both a neutrosophic left zero divisor and a neutrosophic right zero divisor of that element.
Example 3. Let’s consider the set ( {a, b, c}, *, # ), where the laws are defined as follows.
Law * is well-defined, commutative (since its matrix into the Cayley Table is symmetric with respect to the main diagonal), and associative:
Let’s prove the associativity: x * (y * z) = (x * y) * z, for any x, y, z ∊ {a, b, c).
- (1)
If there is at least one “a” among x, y, z, then the result is:
x * (y * z) = a and (x * y) * z = a, since “a” transforms everything into “a” according to the above table,
i.e., a * a = a * b = b * a = a * c = c * a = a.
- (2)
If there are only b’s, then b * (b * b) = b and (b * b) * b = b.
- (3)
If there are only c’s, then c * (c * c) = c and (c * c) * c = c.
- (4)
If there are two b’s and one c, or two c’s and one b, then x * (y * z) = a and (x * y) * z = a,
Since b multiplied (*) with c will get a (or b * c = c * b = a) and further one “a” transforms everything into a [as at point 1 above].
The neutrosophic triplets with respect to the law * are: (a, a, a)*, (a, a, b)*, (a, a, c)*, (b, b, b)*, (c, c, c)*.
The law * has no classical unitary element.
Hence, ({a, b, c}, *) is a commutative neutrosophic triplet group.
Law # is well-defined, commutative (since its matrix into the below Cayley Table is symmetric with respect to the main diagonal), and associative:
Associativity is proved since for any x, y, z ∊ {a, b, c), x # (y # z) = a and (x # y) # z = a because all multiplications (#) give as result “a”.
Let’s prove the distributivity of # with respect to *.
For any x, y, z ∊ {a, b, c), x # (y * z) = a, since the multiplication (#) of anything gives “a”, and (x # y) * (x # z) = a*a = a.
The set ({a, b, c}, #) is not a neutrosophic triplet set, since there is only one neutrosophic triplet (a, a, a) {we have no corresponding neutrosophic triplet for b, nor for c}, and consequently ({a, b, c}, #) is not a neutrosophic triplet group.
The law # has no classical unitary element.
Hence, NTR = ( {a, b, c}, *, #) is a commutative neutrosophic triplet ring, and not a neutrosophic triplet field.
Theorem 1. Let NTR be a commutative neutrosophic triplet ring and such that a, b, neut#(a), neut#(b), neut(a#b), and anti#(a#b) are cancellable and that neut#(a), neut#(b) and anti#(a), anti#(b) do exist in NTR. Then
- 1.
1.,
- 2.
,
- 3.
; and
- 4.
.
Proof. (1) and (2) are similar to the following.
(3) Consider the left-hand side, with
. Multiply by
a to the left and by
b to the right; then we have
since # is associative.
Now we consider the right-hand side; we have
. Multiplying by
a to the left and by
b to the right, we have
since # is associative and commutative,
Thus, LHS = (a#b) = (a#b)#neut#(a#b) = RHS.
(4) Considering the left-hand side, we have anti#(a)#anti#(b).
Multiplying by
a to the left and by
b to the right, we have
using the previous proved result.
Now consider the right-hand side, where we have anti#(a#b).
Multiplying by
a to the left and by
b to the right, we have
□
Open Question on Cancellability
The “cancellability” condition in Theorem 1 is a heavy condition.
Using only commutativity and associativity of a law (without cancellability), it is sometimes possible to prove some neutrosophic triplet identities, but other times not.
In Example 3, the law * does not satisfy the cancellability property, since
a * b = a * c but
b c therefore
a is not cancellable, similarly
b * a = b * c but
a c so
b is not cancellable, and
c * a = c * b but
b c therefore
c is not cancellable either, yet the law * satisfies the first claim of the Theorem 1:
because
but it does not satisfy the second claim of Theorem 1:
because
while
= anti(a) = {a, b, c}, since the element a has three anti’s, resulted from the following neutrosophic triplets:
(a, a, a), (a, a, b), (a, a, c). But
{a, b} ≠ {a, b, c}.Our open question is: When the cancellability property of the elements of a neutrosophic triplet set is needed, and when it is not, in order for the neutrosophic triplet identities to be valid?
Definition 10. Let be a neutrosophic triplet ring and let be a subset of . Then is called a neutrosophic triplet subring of NTR if is a neutrosphic triplet ring.
Definition 11. Let be a neutrosophic triplet ring and I be a subset of NTR. Then I is called a neutrosophic triplet ideal of NTR if the following conditions are satisfied.
- 1.
is a neutrosophic triplet subgroup of ; and
- 2.
For all and , and .
Theorem 2. Every neutrosophic triplet ideal is trivially a neutrosophic triplet subring, but the converse is not true in general.
Remark 2. Let be a neutrosophic triplet ring and let . Then the following are true.
- 1.
anti*(a) in general are not unique in NTR.
- 2.
anti#(a) (if they exist for some element a) in general are not unique in NTR.
Definition 12. Let be a neutrosophic triplet ring and let . Then is called a neutroosphic nilpotent element if , for some positive integer , where (a occurs n times).
In the previous Example 3, one replaces a = 0, b = 2, c = 4, then NTR2 = ( {0, 2, 4}, *, #) is a commutative neutrosophic triplet ring, where (2#)2 = 2#2 = 0 with 2 ≠ 0, and (4#)2 = 4#4 = 0 with 4 ≠ 0, therefore the non-zero elements 2 and 4 are neutrosophic nilpotent elements in NTR2.
Also, since 2#4 = 4#2 = 0, we say that 2 and 4 are neutrosophic zero-divisors in NTR2.
Theorem 3. Let NTR be a commutative neutrosophic triplet ring and such that neut#(an), and anti#(an) do exist in NTR for an integer n 1 . Let a, neut#(a) be cancellable in NTR. Then
- 1.
(neut# (a))n =neut#(an),
- 2.
(anti#(a))n =anti#(an)
Proof. We prove by mathematical induction.
In Theorem 1(3), taking
a =
b, we have
We assume that our equality is true for any positive integer up to
n − 1, that is
neut#(an−1)=(neut#(a))n−1, and we need to prove it for
n. By Theorem 1(3)
(2): similar to (1). □
Theorem 4. Let NTR be a commutative neutrosophic triplet ring and let such that neut#(ak), and anti#(ak) do exist in NTR for an integer k 1. If a is a neutrosophic nilpotent, that is, an = 0 for some integer n > 1, then the following are true.
- 1.
(neut#(a))n = neut#(0); and
- 2.
(anti#(a))n = anti*(0).
Proof. (1) Suppose that
is a neutrosophic nilpotent in NTR and let a
n = 0 for some integer n > 1. Using Theorem 3(1) and (2), we have
□
5. Neutrosophic Triplet Fields
In this section, we study neutrosophic triplet fields and some of their interesting properties.
Definition 15. Let be a neutrosophic triplet set together with two binary operations and #. Then is called a neutrosophic triplet field if the following conditions hold.
- 1.
is a commutative neutrosophic triplet group with respect to *.
- 2.
is a neutrosophic triplet group with respect to .
- 3.
and for all .
Example 4. M6 = {0, 2, 3, 4} is a commutative neutrosophic group under multiplication law # modulo 6 (Example 1). The Cayley Table for Law # is as the following:
# | 0 | 2 | 3 | 4 |
0 | 0 | 0 | 0 | 0 |
2 | 0 | 4 | 0 | 2 |
3 | 0 | 0 | 3 | 0 |
4 | 0 | 2 | 0 | 4 |
Now we define a law * for the set M6 as the following table:
* | 0 | 2 | 3 | 4 |
0 | 0 | 0 | 0 | 0 |
2 | 0 | 2 | 0 | 0 |
3 | 0 | 0 | 3 | 0 |
4 | 0 | 0 | 0 | 4 |
It is easily seen that are neutrosophic triplets, the law * is well defined and commutative. Let us prove its associative:
If a = b = c = 0 then a * (b * c) = 0 = (a * b) * c.
If a = b = c = 2 then a * (b * c) = 2 = (a * b) * c.
If a = b = c = 3 then a * (b * c) = 3 = (a * b) * c.
If a = b = c = 4 then a * (b * c) = 4 = (a * b) * c.
If at least two of a, b and c are different, we have a * (b * c) = 0 = (a * b) * c.
So associative law for * is true. Hence M6 is a commutative neutrosophic group under the law *.
Also it is easily check that a # (b * c) = (a # b) * (a # c) for all a, b and c in M5 is satisfied. (Note that * and # are commutative). So (M5 *,#) is NTF.
Proposition 1. A neutrosophic triplet field always has an anti(a) for every with respect to both laws * and #.
Proof. The proof is straightforward. □
Theorem 6. A neutrosophic triplet ring is not in general a neutrosophic triplet field.
Counterexample is done in Example 3.
Theorem 7. A neutrosophic triplet field is not in general an integral neutrosophic triplet domain .
Theorem 8. Assume that is a neutrosophic triplet ring homomorphism. The following then hold.
- 1.
If is a neutrosophic triplet subring then is a neutrosophic triplet subring of .
- 2.
If is a neutrosophic triplet subring of then is a neutrosophic triplet subring of .
- 3.
If is a neutrosophic triplet ideal of , then is a neutrosophic triplet ideal of .
- 4.
If is onto, and is an ideal of , then is an ideal of .
Proof. (1) Let
, then a * b
S, neut*(a)
S, anti*(a)
S. Then
and
but
, since
is a homomorphism. Thus, we have proved that if
then
. Since neut*(a) and anti*(a)
,
since
is a homomorphism. But f(neut*(a)) = neut
⊕f(a), and f(anti*(a)) = anti
⊕f(a). Therefore, if
, then neut
⊕f(a) = f(neut*(a))
and, similarly,
Now, if
, then
Since
,
But
Therefore, if
then
(2) Let a, b ∊ . Then f(a), f(b) ∊ U. = f(a*b) ∊ U and = ∊ U. Then: a*b, a#b ∊. Since a ∊, then f(a) ∊ U. But also , because U is a neutrosophic subring of NTR2 and f is a neutro-homomorphism. But , whence
(3)
Let
a ∊
and
r ∊
NTR1. Then
f(a) ∊
I and
f(r) ∊
NTR2. Because
f is a neutro-homomorphism and
I an ideal of NTR
2, one has:
hence
(4) Let
and
. Since
is onto, then
such that
and
such that
.
h#s ∊
J because J is an ideal of
NTR1. Then:
which is true, since
, which is an ideal in
, while
. □