Abstract
The purpose of this study is to obtain the commutativity of a 3-prime near ring satisfying some differential identities on Jordan ideals involving derivations and multiplicative derivations. Further, herein we discuss some examples to show the necessity of the hypothesis to our results.
1. Introduction
A left near ring is a triplet , where + and · are two binary operations such that (i) is a group, (ii) is a semigroup, and (iii) for every . Analogously, if instead of (iii), satisfies the right distributive law, then is said to be a right near ring. Therefore, near rings are generalized rings, need not be commutative, and most importantly, only one distributive law is postulated (e.g., Example 1.4, Pilz [1]). A near ring is known as zero-symmetric if for every (left distributive law gives that ). Throughout the manuscript, represents a zero-symmetric left near ring with as its multiplicative center. For , the symbols and denote the commutator and the anticommutator , respectively. A near ring is known as 2-torsion free if ⇒ for every . A near ring is known as 3-prime if for , ⇒ or . Bell and Mason [2] initiated the study of derivation in near rings. An additive mapping is known as a derivation on a near ring if or equivalently as in [3], for all . The commutative property of prime (semiprime) rings with some suitable constraints on derivations has been established by various authors (see [4,5,6,7,8,9,10,11]). Some comparable results on near rings have also been obtained, (c.f. [2,3,12,13,14,15,16,17]). An additive map is known as commuting on a non empty subset of a near ring if for all . An additive subgroup of a near ring is known as a Jordan ideal of if and for all and . Daif and Bell [7] established the following result: Let be a nonzero ideal of a prime ring . If d is a derivation on satisfying for all , then is commutative. In [18], Boua and Oukhtite proved that if a 3-prime near ring with a nonzero derivation d satisfying either or for every , then is a commutative ring. Further, Boua [19] proved that if is a semigroup ideal of a 3-prime near ring and d is a derivation on satisfying any one of the following conditions: (i) , (ii) , (iii) , (iv) , or (v) for all , then is a commutative ring.
A mapping is known as a multiplicative derivation on a ring if for every . In [20], the concept of multiplicative derivation in rings was introduced by Daif and it was inspired by Martindale [21]. In [22], Goldmann and Šemrl studied these mappings and provided the full description of such mappings (for more details, we refer to [20] and [22]). Let be a ring of all real valued continuous functions. Define a map by
Then it is easy to verify that for all but . A mapping (not necessarily additive) is known as a multiplicative derivation on a near ring if for every .
In this manuscript, we show the commutativity condition for a 3-prime near ring if any one of the following holds: (i) , (ii) , (iii) , (iv) , (v) for all and , a Jordan ideal of , where d, , are derivations on .
2. Preliminaries
In this section, we state some basic lemmas to establish our main results.
Lemma 1.
([2], Lemma 3) Let d be a nonzero derivation on a 3-prime near ring .
- (i)
- If is 2-torsion free, then .
- (ii)
- If and , then .
Lemma 2.
([23], Lemma 3) Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . If , then is a commutative ring.
Lemma 3.
([24], Corollary 3) Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . If d is a derivation on such that , then either or the elements of commute under the multiplication of .
Lemma 4.
Let d be a multiplicative derivation on a near ring . Then
3. Main Results
3.1. Commutativity Conditions Involving Derivations
Bell and Daif [6] showed the following result: If is a 2-torsion free prime ring admitting a strong commutativity preserving (in short, SCP) derivation d, i.e., d satisfies for every , then is commutative. In this section, we extend this result for a 3-prime near ring in two directions. First of all, we consider two derivations instead of one derivation, and secondly, we prove the commutativity of a 3-prime near ring in place of a ring in case of a Jordan ideal of .
Theorem 1.
Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . If are two nonzero derivations on such that is commuting on and for all and , then either on or is a commutative ring.
Proof.
By hypothesis,
Applying the definition of and using Lemma 4, we arrive at
Since is commuting on , so the last expression yields that
By 3-primeness of , we obtain
If for all , then our hypothesis becomes for all and which means that for all . Therefore, (5) becomes
Hence, by Lemma 2, we obtain the result. □
The example given below illustrates that we cannot omit the 3-prime condition in Theorem 1.
Example 1.
Suppose that is a zero-symmetric non abelian left near ring and let
Then is zero-symmetric non abelian left near ring w.r.t. addition and multiplication of matrices. Define mappings by
Now consider
It is easy to verify that , are nonzero derivations on a non 3-prime near ring , is a nonzero Jordan ideal of satisfying for all and . However, is not commutative.
Theorem 2.
Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . If d is a nonzero derivation on satisfying for all and , then is a commutative ring.
Proof.
By hypothesis,
Using the hypothesis, we have
which reduces to
Substituting for u in (7) and using it again, we find that
i.e., for all and . As is 3-prime, we obtain
Assume that there exists such that , then by hypothesis
which gives
Applying Lemma 4 and using (9) in above expression, we get
Theorem 3.
Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . If d is a nonzero derivation on satisfying for all and , then either the elements of commute under the multiplication of or is a commutative ring.
Proof.
By hypothesis,
The last expression yields that
Since is 3-prime, we obtain
If for all , then replacing k by , we have
Putting instead of v in the previous expression and using it again, we see that
Applying Lemma 1(ii), we obtain for all . Therefore, (13) together with Lemma 2 yield that either the elements of commute under multiplication of or is commutative. □
Theorem 4.
Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . If d is a derivation on satisfying for all and , then either or the elements of commute under the multiplication of .
Proof.
By hypothesis,
After solving this expression, we find that
Invoking Lemma 2, the last expression yields that for all or is a commutative ring.
If is commutative, then our hypothesis becomes for all and . By 2-torsion freeness of , we have for all and . Replacing u by and using the fact that is 3-prime, we find that for all . Therefore in both cases, we arrive at for all . Hence, by Lemma 3, we conclude the result. □
In [9], Herstein established that if is a prime ring of and d is a derivation on such that for all , then is commutative. Motivated by Herstein’s result, Bell and Mason [2] extended the result for near rings as follows: A 2-torsion free 3-prime near ring is a commutative ring if it admits a nonzero derivation d satisfying for every . Now we prove the following result:
Theorem 5.
Let be a nonzero Jordan ideal of a 3-prime near ring . If d is a nonzero derivation on satisfying for all and , then .
Proof.
By hypothesis,
Using Lemma 4, we find that
Substituting in place of u in above expression, we get
which implies that
Replacing w by in (17) and using it again, we obtain for all and . In view of 3-primeness of together with Lemma 1(i), we obtain , which completes the proof. □
The following example shows the necessity of to be 3-prime in the hypothesis in Theorems 2–5.
Example 2.
Suppose that is a zero-symmetric non abelian left near ring. Let
It is easy to verify that is a non 3-prime, zero-symmetric, non abelian, left near ring w.r.t. addition and multiplication of matrices, and is a nonzero Jordan ideal of . Define by It can be easily seen that d is a nonzero derivation on satisfying
- (i)
- for all and ;
- (ii)
- for all and ;
- (iii)
- for all and ;
- (iv)
- for all and .
However, is not commutative.
3.2. Commutativity Conditions Involving Multiplicative Derivation
Recently, Bedir and Gölbaşi [25] proved that a 3-prime near ring with multiplicative derivation d is commutative if one of the following holds: (i) , (ii) , (iii) , or (iv) , (v) for every . More recently, Mamouni et al. [26] proved that a 2-torsion free prime ring equipped with a generalized derivation is commutative if any one of the following holds: (i) , (ii) , or (iii) for every , a Jordan ideal of . Further, they obtained the same results for to be a *-prime ring and to be a *-Jordan ideal.
In this line of investigation, we obtain the commutativity of a 3-prime near ring with a multiplicative derivation d in case of a Jordan ideal of satisfying one of the following: (i) , (ii) , (iii) , or (iv) for all and , where is a Jordan ideal of .
Theorem 6.
Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . Then admits no multiplicative derivation d satisfying for all and .
Proof.
By hypothesis,
Substituting for u in (19) and using (19) again, we find that for all and . Since is 3-prime, we have
Assume that for all and since together with 2-torsion freeness gives for all . Now replacing u by in our hypothesis, we have
which reduces to
Using (21), we find that for all and . By 3-primeness of , we get for all , a contradiction. Therefore, (20) yields that for all and by an application of Lemma 2, we get that is commutative. Hence, our hypothesis becomes for all and . Since is 2-torsion free, we obtain for all and . Putting in place of u and since is 3-prime, we find that for all , a contradiction. □
Theorem 7.
Let be a nonzero Jordan ideal of a 2-torsion free 3-prime near ring . If d is a multiplicative derivation on satisfying one of the following conditions:
- (i)
- for all and ;
- (ii)
- for all and ;
- (iii)
- for all and ,
then either on or is a commutative ring.
Proof.
Suppose that
Applying Lemma 4 and (22), we obtain
Putting instead of u in (23) and using (23) again, we get for all and . As is 3-prime, we have either or for all . Hence, by Lemma 2, the last expression gives either for all or is a commutative ring.
By hypothesis,
By our hypothesis, we have
Now substituting in place of u in (25) and using (25) again, we get for all and . Invoking Lemma 2 together with the 3-primeness of , we conclude the result.□
By hypothesis,
Theorem 8.
Let be a nonzero Jordan ideal of a 3-prime near ring . If d is a multiplicative derivation on satisfying for all and , then .
Proof.
By hypothesis,
Applying Lemma 4 and (28), we obtain
Since is 3-prime, we find that for all . Therefore, our hypothesis gives for all and . Putting instead of u, we have for all and . Replacing u by in the previous expression and using the 3-primeness of , we obtain our result. □
Now we discuss an example which demonstrates that the 3-prime condition in Theorems 6–8 is essential.
Example 3.
Suppose that is a zero-symmetric non abelian left near ring. Consider
It is easy to check that is a non 3-prime, zero-symmetric, non abelian, left near ring w.r.t. addition and multiplication of matrices and , a Jordan ideal of . Define by It is easy to see that d is a nonzero multiplicative derivation on satisfying
- (i)
- for all and ;
- (ii)
- for all and ;
- (iii)
- for all and ;
- (iv)
- for all and ;
- (v)
- for all and .
However, is not commutative.
For a near ring —a graph in which vertices are the elements of , and for any two vertices , we have or if u and v are adjacent—it is known as the prime graph ([27]) of and is represented by . Easily, we observe that is a star graph if is prime. For a commutative ring , a graph in which the vertices are the set of nonzero zero-divisors of and for any two vertices , we have , and if u and v are joined by an edge, is known as the zero-divisor graph of . We have the following corollary:
Corollary 1.
Suppose that is a 3-prime near ring and its prime graph is star. If d is a derivation on satisfying any one of the following: (i) , (ii) , (iii) , (iv) , or (v) for all , then the zero-divisor graph of is a subgraph of .
4. Discussion
Near rings are generalized rings, since addition is not commutative and the most important fact is only one distributive law is needed. Upon comparing with the standard class of rings, endomorphism rings of abelian groups, we can see that ring theory describes a "linear theory of group mappings," while near rings deal the general "nonlinear theory." A great number of linear results have been transferred to the general nonlinear case with some suitable changes. In the present manuscript, we have generalized the results which have been established for "abelian group mappings" to "non-abelian group mappings." The results of near rings can be used in various fields inside and outside of pure mathematics. We can construct efficient codes and block designs with the help of finite near rings. Inside mathematics, there are several applications of near ring theory in functional analysis, algebraic topology, and category theory, and outside mathematics, there are applications in digital computing, automata theory, sequential mechanics, and combinatorics (see [28] and the references therein).
5. Conclusions
In future research, one can discuss the following issues: (i) Theorems 1–8 can be proven by replacing derivation d by a generalized derivation (or multiplicative generalized derivation), keeping more constraints on derivations. (ii) The commutativity of semiprime near rings is another interesting work for the future.
Author Contributions
Supervision, A.A.; Writing–original draft, I.u.H.; Writing–review & editing, I.u.H. All authors contributed equally. All authors have read and agreed to the published version of the manuscript.
Funding
This research does not receive any external funding.
Acknowledgments
The authors are very thankful to the refrees for their valuable comments and suggestions.
Conflicts of Interest
The authors declare no conflict of interest.
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