Let A be a unital ∗-algebra containing a non-trivial projection. In this paper, we prove that if a map Ω : A → A such that
Ω([K,F]∗⊙D)=[Ω(K),F]∗⊙D+[K,Ω(F)]∗⊙D+[K,F]∗⊙Ω(D),
where [K,F]∗=KF−FK∗ and K⊙F=K∗F+FK∗ for all K,F,D∈A, then Ω is an additive ∗-derivation. Furthermore, we extend its results on factor von Neumann algebras, standard operator algebras and prime ∗-algebras. Additionally, we provide an example illustrating the existence of such maps.
Citation: Junaid Nisar, Turki Alsuraiheed, Nadeem ur Rehman. Nonlinear mixed type product [K,F]∗⊙D on ∗-algebras[J]. AIMS Mathematics, 2024, 9(8): 21596-21608. doi: 10.3934/math.20241049
[1] | Zhonghua Wang, Xiuhai Fei . Maps on C∗-algebras are skew Lie triple derivations or homomorphisms at one point. AIMS Mathematics, 2023, 8(11): 25564-25571. doi: 10.3934/math.20231305 |
[2] | Mohd Arif Raza, Abdul Nadim Khan, Husain Alhazmi . A characterization of b−generalized derivations on prime rings with involution. AIMS Mathematics, 2022, 7(2): 2413-2426. doi: 10.3934/math.2022136 |
[3] | Fenhong Li, Liang Kong, Chao Li . Non-global nonlinear mixed skew Jordan Lie triple derivations on prime ∗-rings. AIMS Mathematics, 2025, 10(4): 7795-7812. doi: 10.3934/math.2025357 |
[4] | Liang Kong, Chao Li . Non-global nonlinear skew Lie triple derivations on factor von Neumann algebras. AIMS Mathematics, 2022, 7(8): 13963-13976. doi: 10.3934/math.2022771 |
[5] | Mohd Arif Raza, Huda Eid Almehmadi . Lie (Jordan) σ−centralizer at the zero products on generalized matrix algebra. AIMS Mathematics, 2024, 9(10): 26631-26648. doi: 10.3934/math.20241295 |
[6] | Wenbo Huang, Jiankui Li, Shaoze Pan . Some zero product preserving additive mappings of operator algebras. AIMS Mathematics, 2024, 9(8): 22213-22224. doi: 10.3934/math.20241080 |
[7] | Huiting Zhang, Yuying Yuan, Sisi Li, Yongxin Yuan . The least-squares solutions of the matrix equation A∗XB+B∗X∗A=D and its optimal approximation. AIMS Mathematics, 2022, 7(3): 3680-3691. doi: 10.3934/math.2022203 |
[8] | Xiuhai Fei, Zhonghua Wang, Cuixian Lu, Haifang Zhang . Higher Jordan triple derivations on ∗-type trivial extension algebras. AIMS Mathematics, 2024, 9(3): 6933-6950. doi: 10.3934/math.2024338 |
[9] | Ahmad A. Abubaker, Khaled Matarneh, Mohammad Faisal Khan, Suha B. Al-Shaikh, Mustafa Kamal . Study of quantum calculus for a new subclass of q-starlike bi-univalent functions connected with vertical strip domain. AIMS Mathematics, 2024, 9(5): 11789-11804. doi: 10.3934/math.2024577 |
[10] | Ai-qun Ma, Lin Chen, Zijie Qin . Jordan semi-triple derivations and Jordan centralizers on generalized quaternion algebras. AIMS Mathematics, 2023, 8(3): 6026-6035. doi: 10.3934/math.2023304 |
Let A be a unital ∗-algebra containing a non-trivial projection. In this paper, we prove that if a map Ω : A → A such that
Ω([K,F]∗⊙D)=[Ω(K),F]∗⊙D+[K,Ω(F)]∗⊙D+[K,F]∗⊙Ω(D),
where [K,F]∗=KF−FK∗ and K⊙F=K∗F+FK∗ for all K,F,D∈A, then Ω is an additive ∗-derivation. Furthermore, we extend its results on factor von Neumann algebras, standard operator algebras and prime ∗-algebras. Additionally, we provide an example illustrating the existence of such maps.
Consider an algebra A defined over the complex field C. A map ∗:A→A is called an involution if the following conditions hold for all K,F∈A and α∈C. (i) (K+F)∗=K∗+F∗; (ii) (αK)∗=ˉαK∗; (iii) (KF)∗=(F)∗(K)∗ and (K∗)∗=K. An algebra A with the involution ∗ is called the ∗-algebra. For K,F∈A, we call [K,F]∗=KF−FK∗ the skew Lie product, [K,F]∙=KF∗−FK∗ denotes the bi-skew Lie product and K⊙F=K∗F+FK∗ denotes the bi-skew Jordan product. The skew Lie product, the Jordan product, and the bi-skew Jordan product have become increasingly relevant in various research fields, and numerous authors have shown a keen interest in their exploration. This is evident from the numerous studies by authors (see [1,2,3,5,7,8,9,10,13,15,16]). Recall that an additive map Ω:A→A is called an additive derivation if Ω(KF)=Ω(K)F+KΩ(F) for all K,F∈A. If Ω(K∗)=Ω(K)∗ for all K∈A, then Ω is an additive ∗-derivation. Let Ω:A→A be a map (without the additivity assumption). We say Ω is a nonlinear skew Lie derivation or nonlinear skew Lie triple derivation if
Ω([K,F]∗)=[Ω(K),F]∗+[K,Ω(F)]∗ |
or
Ω([[K,F]∗,D]∗)=[[Ω(K),F]∗,D]∗+[[K,Ω(F)]∗,D]∗+[[K,F]∗,Ω(D)]∗ |
for all K,F,D∈A. Similarly, a map Ω:A→A is said to be a nonlinear bi-skew Lie derivation or nonlinear bi-skew Lie triple derivation if
Ω([K,F]∙=[Ω(K),F]∙+[K,Ω(F)]∙ |
or
Ω([[K,F]∙,D]∙)=[[Ω(K),F]∙,D]∙+[[K,Ω(F)]∙,D]∙+[[K,F]∙,Ω(D)]∙ |
for all K,F,D∈A. In 2021, A. Khan [4] established a proof demonstrating that any multiplicative or nonadditive bi-skew Lie triple derivation acting on a factor Von Neumann algebra can be characterized as an additive ∗-derivation.
Numerous authors have recently explored the derivations and isomorphisms corresponding to the novel products created by combining Lie and skew Lie products, skew Lie and skew Jordan products see [6,11,12,14]. As an illustration, Li and Zhang [6] delved into an investigation focused on understanding the arrangement and properties of the nonlinear mixed Jordan triple ∗-derivation within the domain of ∗-algebras. In 2022, Rehman et. al. [12] mixed the concepts of Jordan and Jordan ∗-product and gave the complete characterization of nonlinear mixed Jordan ∗-triple derivation on ∗-algebras. Inspired by the above results, in the present paper, we combined the skew Lie product and bi-skew Jordan product and defined nonlinear mixed bi-skew Jordan triple derivation on ∗-algebras. A map Ω: A → A is called nonlinear mixed bi-skew Jordan triple derivations if
Ω([K,F]∗⊙D)=[Ω(K),F]∗⊙D+[K,Ω(F)]∗⊙D+[K,F]∗⊙Ω(D), |
for all K,F,D∈A. Our proof establishes that when Ω represents a nonlinear mixed bi-skew Lie triple derivation acting on ∗-algebras, it necessarily possesses an additive ∗-derivation. In simpler terms, the study demonstrates that specific properties, such as additivity and self-adjointness, can be attributed to the nature of nonlinear mixed bi-skew Jordan triple derivations on ∗-algebras.
Theorem 2.1. Let A be a unital ∗-algebra with unity I containing a non-trivial projection P. Suppose that A satisfies
XAP=0⟹X=0, | (▲) |
and
XA(I−P)=0⟹X=0. | (▼) |
Define a map Ω:A→A such that
Ω([K,F]∗⊙D)=[Ω(K),F]∗⊙D+[K,Ω(F)]∗⊙D+[K,F]∗⊙Ω(D), |
then Ω is an additive ∗-derivation.
Let P=P1 be a non-trivial projection in A, and P2=I−P1, where I is the unity of this algebra. Then by Peirce decomposition of A, we have A=P1AP1⊕P1AP2⊕P2AP1⊕P2AP2 and, denote A11=P1AP1,A12=P1AP2,A21=P2AP1 and A22=P2AP2. Note that any K∈A can be written as K=K11+K12+K21+K22, where Kij∈Aij and K∗ij∈Aji for i,j=1,2.
Several lemmas are used to prove Theorem 2.1.
Lemma 2.1. Ω(0)=0 and Ω(I)=Ω(I)∗.
Proof. It is trivial that
Ω(0)=Ω([0,0]∗⊙0)=[Ω(0),0]∗⊙0+[0,Ω(0)]∗⊙0+[0,0]∗⊙Ω(0)=0. |
We can easily see that
Ω([I,iI]∗⊙I)=0. |
From the other side, we yield
Ω([I,iI]∗⊙I)=[Ω(I),iI]∗⊙I+[I,Ω(iI)]∗⊙I+[I,iI]∗⊙Ω(I)=−2iΩ(I)∗+2iΩ(I). |
From the equations above, we can deduce
Ω(I)=Ω(I)∗. |
The proof is now concluded.
Lemma 2.2. For any K12∈A12,K21∈A21, we have
Ω(K12+K21)=Ω(K12)+Ω(K21). |
Proof. Let M=Ω(K12)+Ω(K21)−Ω(K12)−Ω(K21). We have
Ω([K12+K21,P1]∗⊙P2)=[Ω(K12+K21),P1]∗⊙P2+[K12+K21,Ω(P1)]∗⊙P2+[K12+K21,P1]∗⊙Ω(P2). |
Alternatively, it follows from [K12,P1]∗⊙P2=0 that
Ω([K12+K21,P1]∗⊙P2)=Ω([K12,P1]∗⊙P2)+Ω([K21,P1]∗⊙P2)=[Ω(K12),P1]∗⊙P2+[K12,Ω(P1)]∗⊙P2+[K12,P1]∗⊙Ω(P2)+[Ω(K21),P1]∗⊙P2+[K21,Ω(P1)]∗⊙P2+[K21,P1]∗⊙Ω(P2). |
From the last two expressions, we conclude [M,P1]∗⊙P2=0. That means P1M∗P2−P2MP1=0. By multiplying P2 from the left, we find P2MP1=0. In similar way, we can easily show that P1MP2=0.
Also, [i(P1−P2),I]∗⊙K12=0. Thus,
Ω([i(P1−P2),I]∗⊙(K12+K21))=Ω([i(P1−P2),I]∗⊙K12)+Ω([i(P1−P2),I]∗⊙K21)=[Ω(i(P1−P2)),I]∗⊙K12+[i(P1−P2),Ω(I)]∗⊙K12+[i(P1−P2),I]∗⊙Ω(K12)+[Ω(i(P1−P2)),I]∗⊙K21+[i(P1−P2),Ω(I)]∗⊙K21+[i(P1−P2),I]∗⊙Ω(K21). |
On the other side, we have
Ω([i(P1−P2),I]∗⊙(K12+K21))=[Ω(i(P1−P2)),I]∗⊙(K12+K21)+[i(P1−P2),Ω(I)]∗⊙(K12+K21)+[i(P1−P2),I]∗⊙Ω(K12+K21). |
From the last two expressions, we obtain [i(P1−P2),I]∗⊙M=0. That means −2iP1M+2iP2M−2iMP1+2iMP2=0. By pre and post multiplying by P1 from both sides, we get P1MP1=0. In the similar way, we can show that P2MP2=0. Hence, M=0, i.e.,
Ω(K12+K21)=Ω(K12)+Ω(K21). |
The proof is now concluded.
Lemma 2.3. For any Kii∈Aii,Kij∈Aij,1≤i,j≤2, we have
Ω(Kii+Kij+Kji)=Ω(Kii)+Ω(Kij)+Ω(Kji). |
Proof. First, we will demonstrate the case when \(i = 1\) and \(j = 2\). Let M=Ω(K11+K12+K21)−Ω(K11)−Ω(K12)−Ω(K21). Since [K11,P1]∗⊙P2=0 and using Lemma 2.2, we have
Ω([(K11+K12+K21),P1]∗⊙P2)=Ω([K11,P1]∗⊙P2)+Ω([K12,P1]∗⊙P2)+Ω([K21,P1]∗⊙P2)=[Ω(K11),P1]∗⊙P2+[K11,Ω(P1)]∗⊙P2+[K11,P1]∗⊙Ω(P2)+[Ω(K12),P1]∗⊙P2+[K12,Ω(P1)]∗⊙P2+[K12,P1]∗⊙Ω(P2)+[Ω(K21),P1]∗⊙P2+[K21,Ω(P1)]∗⊙P2+[K21,P1]∗⊙Ω(P2). |
On the other side, we have
Ω([(K11+K12+K21),P1]∗⊙P2)=[Ω(K11+K12+K21),P1]∗⊙P2+[(K11+K12+K21),Ω(P1)]∗⊙P2+[(K11+K12+K21),P1]∗⊙Ω(P2). |
From the above two expressions, we find [M,P1]∗⊙P2=0, and so, P2MP1=0. Similarly, P1MP2=0. Now, for all X12∈A12, we have
Ω([X12,(K11+K12+K21)]∗⊙P2)=[Ω(X12),(K11+K12+K21)]∗⊙P2+[X12,Ω(K11+K12+K21)]∗⊙P2+[X12,(K11+K12+K21)]∗⊙Ω(P2). |
Also, [X12,K11]∗⊙P2=0 and using Lemma 2.2, we get
Ω([X12,(K11+K12+K21)]∗⊙P2)=Ω([X12,K11]∗⊙P2)+Ω([X12,K12]∗⊙P2)+Ω([X12,K21]∗⊙P2)=[Ω(X12),K11]∗⊙P2+[X12,Ω(K11)]∗⊙P2+[X12,K11]∗⊙Ω(P2)+[Ω(X12),K12]∗⊙P2+[X12,Ω(K12)]∗⊙P2+[X12,K12]∗⊙Ω(P2)+[Ω(X12),K21]∗⊙P2+[X12,Ω(K21)]∗⊙P2+[X12,K21]∗⊙Ω(P2). |
From the above two relations, we get [X12,M]∗⊙P2=0. That means −X12M∗P2+P2M∗X∗12=0. By post-multiplying by P2 on both sides, we get −X12M∗P2=0. Therefore, by using (▲) and (▼), we get P2MP2=0. Similarly, P1MP1=0. Hence, M=0. i.e.,
Ω(K11+K12+K21)=Ω(K11)+Ω(K12)+Ω(K21). |
By using the same technique, we can also show for i=2,j=1. The proof is now concluded.
Lemma 2.4. For any Kij∈Aij,1≤i,j≤2, we have
Ω(2∑i,j=1Kij)=2∑i,j=1Ω(Kij). |
Proof. Let M=Ω(K11+K12+K21+K22)−Ω(K11)−Ω(K12)−Ω(K21)−Ω(K22). Since, [K11,P1]∗⊙P2=0 and using Lemma 2.3 that
Ω([(K11+K12+K21+K22),P1]∗⊙P2)=Ω([K11,P1]∗⊙P2)+Ω([K12,P1]∗⊙P2)+Ω([K21,P1]∗⊙P2)+Ω([K22,P1]∗⊙P2)=[Ω(K11)+Ω(K12)+Ω(K21)+Ω(K22),P1]∗⊙P2+[K11+K12+K21+K22,Ω(P1)]∗⊙P2+[K11+K12+K21+K22,P1]∗⊙Ω(P2). |
Alternatively, we have
Ω([(K11+K12+K21+K22),P1]∗⊙P2)=[Ω(K11+K12+K21+K22),P1]∗⊙P2+[(K11+K12+K21+K22),Ω(P1)]∗⊙P2+[(K11+K12+K21+K22),P1]∗⊙Ω(P2). |
From the last two relations, we get [M,P1]∗⊙P2=0. Thus, P1M∗P2−P2MP1=0. Hence, P2MP1=0. Similarly, P1MP2=0.
Now, for any X12∈A12, we have
Ω([X12,K11+K12+K21+K22]∗⊙P2)=[Ω(X12),K11+K12+K21+K22]∗⊙P2+[X12,Ω(K11+K12+K21+K22)]∗⊙P2+[X12,K11+K12+K21+K22]∗⊙Ω(P2). |
Also, [X12,K11]∗⊙P2=0, and using Lemma 2.3, we find
Ω([X12,K11+K12+K21+K22]∗⊙P2)=Ω([X12,K11]∗⊙P2)+Ω([X12,K12]∗⊙P2)+Ω([X12,K21]∗⊙P2)+Ω([X12,K22]∗⊙P2)=[Ω(X12),K11+K12+K21+K22]∗⊙P2+[X12,Ω(K11)+Ω(K12)+Ω(K21)+Ω(K22)]∗⊙P2+[X12,K11+K12+K21+K22]∗⊙Ω(P2). |
Upon comparing the aforementioned two equations, we observe that [X12,M]∗⊙P2=0. On solving, we get P2MP2=0. Similarly, we can show that P1MP1=0. Hence, M=0, i.e.,
Ω(K11+K12+K21+K22)=Ω(K11)+Ω(K12)+Ω(K21)+Ω(K22). |
This ends the proof.
Lemma 2.5. For each K12,F12∈A12 and K21,F21∈A21, we have
(1) Ω(K12+F12)=Ω(K12)+Ω(F12).
(2) Ω(K21+F21)=Ω(K21)+Ω(F21).
Proof. (1) Let M=Ω(K12+F12)−Ω(K12)−Ω(F12). We have,
Ω([K12+F12,P1]∗⊙P2)=[Ω(K12+F12),P1)]∗⊙P2+[K12+F12,Ω(P1)]∗⊙P2+[K12+F12,P1]∗⊙Ω(P2). |
On the other hand, it follows from [K12,P1]∗⊙P2=0 that
Ω([K12+F12,P1]∗⊙P2)=Ω([K12,P1]∗⊙P2)+Ω([F12,P1]∗⊙P2)=[Ω(K12)+Ω(F12),P1]∗⊙P2+[K12+F12,Ω(P1)]∗⊙P2+[K12+F12,P1]∗⊙Ω(P2). |
From the last two relations, we get [M,P1]∗⊙P2=0. This means that P1M∗P2−P2MP1=0. By pre-multiplying P2 on both sides, we get P2MP1=0. Similarly, we can show that P1MP2=0. Now, for any X12∈A12, we have
Ω([X12,K12+F12]∗⊙P2)=[Ω(X12),K12+F12]∗⊙P2+[X12,Ω(K12+F12)]∗⊙P2+[X12,K12+F12]∗⊙Ω(P2). |
On the other hand, it follows from [X12,K12]∗⊙P2=0 that
Ω([X12,K12+F12]∗⊙P2)=Ω([X12,K12]∗⊙P2)+Ω([X12,F12]∗⊙P2)=[[Ω(X12),K12+F12]∗⊙P2+[X12,Ω(K12)+Ω(F12)]∗⊙P2+[X12,K12+F12]∗⊙Ω(P2). |
On comparing the above two relations, we get [X12,M]∗⊙P2=0. On solving, we get P2MP2=0. Similarly, we can show that P1MP1=0. Hence, M=0, i.e.,
Ω(K12+F12)=Ω(K12)+Ω(F12). |
\text{(2)} By using the same technique, we can show that
Ω(K21+F21)=Ω(K21)+Ω(F21). |
The proof is now concluded.
Lemma 2.6. For each Kii,Fii∈Aii such that 1≤i≤2, we have
Ω(Kii+Fii)=Ω(Kii)+Ω(Fii). |
Proof. First, it is prove for i=1. Let M=Ω(K11+F11)−Ω(K11)−Ω(F11). Since, [K11,P1]∗⊙P2=0, we have
Ω([K11+F11,P1]∗⊙P2)=Ω([K11,P1]∗⊙P2)+Ω([F11,P1]∗⊙P2)=[Ω(K11)+Ω(F11),P1]∗⊙P2+[K11+F11,Ω(P1)]∗⊙P2+[K11+F11,P1]∗⊙Ω(P2). |
On the other hand, we have
Ω([K11+F11,P1]∗⊙P2)=[Ω(K11+F11),P1]∗⊙P2+[K11+F11,Ω(P1)]∗⊙P2+[K11+F11,P1]∗⊙Ω(P2). |
Upon comparing the aforementioned two equations, we observe that [M,P1]∗⊙P2=0. On solving, we get P1M∗P2−P2MP1=0. By pre-multiplying by P2 on both sides, we get P2MP1=0. Similarly, P1MP2=0. Now, for any X12∈A12, we have
Ω([X12,K11+F11]∗⊙P2)=[Ω(X12),K11+F11]∗⊙P2+[X12,Ω(K11+F11)]∗⊙P2+[X12,K11+F11]∗⊙Ω(P2). |
It follows from [X12,K11]∗⊙P1=0 that
Ω([X12,K11+F11]∗⊙P2)=[Ω(X12),K11+F11]∗⊙P2+[X12,Ω(K11)+Ω(F11)]∗⊙P2+[X12,K11+F11]∗⊙Ω(P2). |
By comparing, we get [X12,M]∗⊙P2=0. That means −X12M∗P2+P2M∗X∗12=0. By pre-multiplying P2 on both sides, we get P2M∗X∗12=0. Thus, by using (▲) and (▼), we get P2MP2=0. Similarly, P1MP1=0. Hence, M=0. This completes the proof.
Lemma 2.7. Ω is an additive map.
Proof. For any K,F∈A, we write K=K11+K12+K21+K22 and F=F11+F12+F21+F22. By using Lemmas 2.4–2.6, we get
Ω(K+F)=Ω(K11+K12+K21+K22+F11+F12+F21+F22)=Ω(K11+F11)+Ω(K12+F12)+Ω(K21+F21)+Ω(K22+F22)=Ω(K11)+Ω(F11)+Ω(K12)+Ω(F12)+Ω(K21)+Ω(F21)+Ω(K22)+Ω(F22)=Ω(K11+K12+K21+F22)+Ω(F11+F12+F21+F22)=Ω(K)+Ω(F). |
Hence, Ω is additive.
Lemma 2.8. The following conditions holds:
(i) Ω(iI)∗=Ω(iI)=0.
(ii) Ω(I)=0.
Proof. (i) It follows from Lemma 2.7 that
Ω([iI,iI]∗⊙I)=Ω(−4I)=−4Ω(I) |
and
Ω([iI,iI]∗⊙I)=[Ω(iI),iI]∗⊙I+[iI,Ω(iI)]∗⊙I+[iI,iI]∗⊙Ω(I)=(iΩ(iI)−iΩ(iI)∗)⊙ I+2iΩ(iI)⊙I−2I⊙Ω(I)=−6iΩ(iI)∗+2iΩ(iI)−4Ω(I). |
From the last two expressions, we get
−3Ω(iI)∗+Ω(iI)=0. | (2.1) |
Also, we can evaluate
Ω([iI,I]∗⊙iI)=Ω(2iI⊙iI)=4Ω(I). |
Alternatively, we can write
Ω([iI,I]∗⊙iI)=[Ω(iI),I]∗⊙iI+[iI,Ω(I)]∗⊙iI+[iI,I]∗⊙Ω(iI)=2iΩ(iI)∗−6iΩ(iI)+4Ω(I)∗. |
By comparing above two equations, and also using Lemma 2.1, we find
Ω(iI)∗−3Ω(iI)=0. | (2.2) |
By using Eqs (2.1) and (2.2), we have
Ω(iI)∗=Ω(iI)=0. |
(ii) In the similar way, we can show that Ω(I)=0.
Lemma 2.9. Ω preserves star, i.e., Ω(K∗)=Ω(K)∗ for all K∈A.
Proof. From Lemma 2.7, we have
Ω([K,iI]∗⊙iI)=Ω(iK−iK∗)⊙iI)=2Ω(K∗)−2Ω(K). |
Alternatively, it follows from Lemma 2.8 that
Ω([K,iI]∗⊙iI)=[Ω(K),iI]∗⊙iI=(iΩ(K)−iΩ(K)∗)⊙iI=2Ω(K)∗−2Ω(K). |
From the above two equations, we obtain
Ω(K∗)=Ω(K)∗ |
for all K∈A. This completes the proof.
Lemma 2.10. We prove that Ω(iK)=iΩ(K) for all K∈A.
Proof. For any K∈A, we have
Ω([iI,I]∗⊙K)=Ω(2iI⊙K)=−4Ω(iK). |
Alternatively, it follows from Lemma 2.8 that
Ω([iI,I]∗⊙K)=[iI,I]∗⊙Ω(K)=(2iI)⊙K=−4iΩ(K). |
From the above two expressions, we obtain
Ω(iK)=iΩ(K). |
Proof of Theorem 2.1. For any K,F∈A, it follows from Lemmas 2.7 that
Ω(K+F)=Ω(K)+Ω(F). | (2.3) |
Also, by using Lemma 2.9 that
Ω(K∗)=Ω(K)∗ | (2.4) |
for all K∈A. Now, we only have to show that Ω is an derivation.
Now, for any K,F∈A, and using Lemma 2.7, we have
Ω([K,I]∗⊙F)=Ω((K−K∗)⊙F)=Ω(K∗F)−Ω(KF)+Ω(FK∗)−Ω(FK). |
Also, using Lemma 2.8 that
Ω([K,I]∗⊙F)=[Ω(K),I]∗⊙F+[K,I]∗⊙Ω(F)=Ω(K)∗F−Ω(K)F+FΩ(K)∗−FΩ(K)+K∗Ω(F)−KΩ(F)+Ω(F)K∗−Ω(F)K. |
By comparing the two equations above, we obtain
Ω(K∗F)−Ω(KF)+Ω(FK∗)−Ω(FK)=Ω(K)∗F−Ω(K)F+FΩ(K)∗−FΩ(K)+K∗Ω(F)−KΩ(F)+Ω(F)K∗−Ω(F)K. | (2.5) |
On the other hand, according to Lemma 2.7, we can infer that
Ω([iK,I]∗⊙iF)=Ω((iK+iK∗)⊙iF)=Ω(K∗F)+Ω(KF)+Ω(FK∗)+Ω(FK). |
Alternatively, by using Lemma 2.8, we find
Ω([iK,I]∗⊙iF)=[Ω(iK),I]∗⊙iF+[iK,I]∗⊙Ω(iF)=Ω(K)∗F+Ω(K)F+FΩ(K)∗+FΩ(K)+K∗Ω(F)+KΩ(F)+Ω(F)K∗+Ω(F)K. |
From the above two expressions, we find
Ω(K∗F)+Ω(KF)+Ω(FK∗)+Ω(FK)=Ω(K)∗F+Ω(K)F+FΩ(K)∗+FΩ(K)+K∗Ω(F)+KΩ(F)+Ω(F)K∗+Ω(F)K. | (2.6) |
Subtracting Eq (2.5) to Eq (2.6), we get
Ω(KF+FK)=Ω(K)F+KΩ(F)+FΩ(K)+Ω(F)K. | (2.7) |
By using Lemma 2.10 and the above equation, we find
Ω(KF−FK)=iΩ((−iK)(F)+(iF)K)=Ω(K)F+KΩ(F)−FΩ(K)−Ω(F)K | (2.8) |
Adding Eqs (2.7) and (2.8), we get
Ω(KF)=Ω(K)F+KΩ(F). | (2.9) |
From Eqs (2.3), (2.4) and (2.9), we get Ω is an additive ∗-derivation. This completes the proof.
Now, we provide an example to demonstrate the necessity of the conditions (▲) and (▼) in Theorem 2.1.
Example 2.1. Consider A={(a0cd)}, the algebra of all lower triangular matrix of order 2 over the field of complex numbers C and I=(1001) be the unity of A. The map ∗:A→A given by ∗(K)=Kθ, where Kθ denotes the conjugate transpose of matrix A, is an involution. Hence, A is a unital ∗-algebra with unity I. Now, define a map Ω:A→A such that Ω(a0cd)=(00−ic0). Note that Ω is a derivation on A. So, it also satisfies
Ω([[K,F]⊙,D]∗)=[[Ω(K),F]⊙,D]∗+[[K,Ω(F)]⊙,D]∗+[[K,F]⊙,Ω(D)]∗ |
for all K,F,D∈A. Let P=(0001) is a non-trivial projection, so P2=P and P∗=P. For W=(0010)≠0∈A and hence WAP=(0) but 0≠W∈A. However, Ω is not an additive ∗-derivation because Ω(K∗)≠(Ω(K))∗ for some K∈A.
The following corollaries arise directly from Theorem 2.1: The algebra of all bounded linear operators on H is denoted by B(H). Let H be a Hilbert space over the field F of real or complex numbers. The dimension of an operator's range is known as its rank. An operator with a finite dimensional range is therefore said to have a finite rank. F(H) is the subalgebra of all bounded linear operators of finite rank on H.
Let H be a Banach space over the real or complex number field F. In the case of F(H)⊆K(H), a subalgebra K(H) of B(H) is referred to as a standard operator algebra.
Corollary 3.1. Let A be a standard operator algebra on an infinite dimensional complex Hilbert space H containing an identity operator I. Suppose that A is closed under adjoint operation. Define Ω:A→A such that
Ω([K,F]∗⊙D)=[Ω(K),F]∗⊙D+[K,Ω(F)]∗⊙D+[K,F]∗⊙Ω(D), |
for all K,F,D∈A, then Ω is an additive ∗-derivation.
Proof. Every standard operator algebra A being a prime algebra is a direct consequence of the Hahn-Banach theorem. As a prime algebra, A naturally fulfills the conditions specified in (▲) and (▼). Consequently, according to Theorem 2.1, it follows that the map Ω described earlier is an additive ∗-derivation.
A von Neumann algebra is defined as a weakly closed self-adjoint subalgebra of B(H) that includes the identity operator, where B(H) is the space of all bounded linear operators on a complex Hilbert space H. In other words, a self-adjoint subalgebra of B(H) that satisfies the double commutant property, that is, M″=M, is considered a von Neumann algebra. In this context, a factor von Neumann algebra is one with a trivial center, which is equal to the intersection of M and its double commutant, M∩M′=CI. Additionally, an abelian von Neumann algebra is one where the center is equal to the algebra itself, that is, Z(M)=M.
Corollary 3.2. Let M ba a factor von Neumann algebra with dimM≥2. Define Ω:M→M such that
Ω([K,F]∗⊙D)=[Ω(K),F]∗⊙D+[K,Ω(F)]∗⊙D+[K,F]∗⊙Ω(D), |
for all K,F,D∈A, then Ω is an ∗-derivation.
Proof. By using [16,Lemma 2.2], it is established that every factor von Neumann algebra M satisfies the conditions outlined in (▲) and (▼). Therefore, applying Theorem 2.1, we conclude that the map Ω described earlier is an additive ∗-derivation within the context of factor von Neumann algebras.
An algebra A is called prime algebra, if KAK={0} for K,F∈A implies either K=0 or F=0.
Corollary 3.3. Let A be a prime ∗-algebra with unit I containing non-trivial projection P. A map Ω:A→A satisfies
Ω([K,F]∗⊙D)=[Ω(K),F]∗⊙D+[K,Ω(F)]∗⊙D+[K,F]∗⊙Ω(D), |
for all K,F,D∈A, then Ω is an additive ∗-derivation.
Proof. By the definition of primeness of A, it is straightforward to observe that A also satisfies (▲) and (▼). Therefore, by Theorem 2.1, we conclude that Ω is an additive ∗-derivation.
All authors are contributed equally.
The authors declare they have not used Artificial Intelligence (AI) tools in the creation of this article.
This study was carried out with financial support from Researchers Supporting Project Number (RSPD2024R934), King Saud University, Riyadh, Saudi Arabia.
The authors declare that they have no conflicts of interest.
[1] | M. Ashraf, M. S. Akhter, M. A. Ansari, Nonlinear bi-skew Lie-type derivations on factor von Neumann algebras, Commun. Algebra, 50 (2022), 4766–4780. https://doi.org/10.1080/00927872.2022.2074027 |
[2] |
D. Huo, B. Zheng, J. Xu, H. Liu, Nonlinear mappings preserving Jordan multiple ∗-product on factor von-neumann algebras, Linear Multilinear A., 63 (2015), 1026–1036. https://doi.org/10.1080/03081087.2014.915321 doi: 10.1080/03081087.2014.915321
![]() |
[3] |
L. Kong, J. Zhang, Nonlinear skew Lie derivations on prime ∗-rings, Indian J. Pure Appl. Math., 54 (2023), 475–484. https://doi.org/10.1007/s13226-022-00269-y doi: 10.1007/s13226-022-00269-y
![]() |
[4] |
A. N. Khan, Multiplicative biskew Lie triple derivations on factor von Neumann algebras, Rocky Mountain J. Math., 51 (2021), 2103–2114. https://doi.org/10.1216/rmj.2021.51.2103 doi: 10.1216/rmj.2021.51.2103
![]() |
[5] |
C. J. Li, F. Y. Lu, Nonlinear maps preserving the Jordan triple 1 ∗-product on von Neumann algebras, Complex Anal. Oper. Theory, 11 (2017), 109–117. https://doi.org/10.1007/s11785-016-0575-y doi: 10.1007/s11785-016-0575-y
![]() |
[6] |
C. J. Li, D. Zhang, Nonlinear mixed Jordan triple ∗-derivations on ∗-algebras, Sib. Math. J., 63 (2022), 735–742. https://doi.org/10.1134/S0037446622040140 doi: 10.1134/S0037446622040140
![]() |
[7] |
C. J. Li, F. F. Zhao, Q. Y. Chen, Nonlinear skew Lie triple derivations between factors, Acta Math. Sin. English Ser., 32 (2016), 821–830. https://doi.org/10.1007/s10114-016-5690-1 doi: 10.1007/s10114-016-5690-1
![]() |
[8] |
C. J. Li, Y. Zhao, F. Zhao, Nonlinear maps preserving the mixed product [A⊙B,C]∗ on von Neumann algebras, Filomat, 35 (2021), 2775–2781. https://doi.org/10.2298/FIL2108775L doi: 10.2298/FIL2108775L
![]() |
[9] |
C. J. Li, Q. Y. Chen, T. Wang, Nonlinear maps preserving the Jordan triple ∗-product on factor von Neumann algebras, Chin. Ann. Math. Ser. B, 39 (2018), 633–642. https://doi.org/10.1007/s11401-018-0086-4 doi: 10.1007/s11401-018-0086-4
![]() |
[10] |
C. J. Li, Y. Zhao, F. F. Zhao, Nonlinear ∗-Jordan-type derivations on ∗-algebras, Rocky Mountain J. Math., 51 (2021), 601–612. https://doi.org/10.1216/rmj.2021.51.601 doi: 10.1216/rmj.2021.51.601
![]() |
[11] |
Y. Pang, D. Zhang, D. Ma, The second nonlinear mixed Jordan triple derivable mapping on factor von Neumann algebras, Bull. Iran. Math. Soc., 48 (2022), 951–962. https://doi.org/10.1007/s41980-021-00555-1 doi: 10.1007/s41980-021-00555-1
![]() |
[12] |
N. Rehman, J. Nisar, M. Nazim, A note on nonlinear mixed Jordan triple derivation on ∗-algebras, Commun. Algebra, 51 (2023), 1334–1343. https://doi.org/10.1080/00927872.2022.2134410 doi: 10.1080/00927872.2022.2134410
![]() |
[13] | A. Taghavi, M. Nouri, M. Razeghi, V. Darvish, Non-linear λ-Jordan triple ∗-derivation on prime ∗-algebras, Rocky Mountain J. Math., 48 (2018), 2705–2716. https://doi.org/10.1216/RMJ-2018-48-8-2705 |
[14] |
L. Y. Xian, Z. J. Hua, Nonlinear mixed Lie triple derivation on factor von neumann algebras, Acta Math. Sin. Chinese Ser., 62 (2019), 13–24. https://doi.org/10.12386/A2019sxxb0002 doi: 10.12386/A2019sxxb0002
![]() |
[15] |
F. Zhang, Nonlinear η-Jordan triple ∗-derivation on prime ∗-algebras, Rocky Mountain J. Math., 52 (2022), 323–333. https://doi.org/10.1216/rmj.2022.52.323 doi: 10.1216/rmj.2022.52.323
![]() |
[16] |
F. F. Zhao, C. J. Li, Nonlinear ∗-Jordan triple derivations on von Neumann algebras, Math. Slovaca, 68 (2018), 163–170. https://doi.org/10.1515/ms-2017-0089 doi: 10.1515/ms-2017-0089
![]() |