Article
Keywords:
commutativity preserving map; automorphism; commutative ring
Summary:
Let $\mathcal {N}=N_n(R)$ be the algebra of all $n\times n$ strictly upper triangular matrices over a unital commutative ring $R$. A map $\varphi $ on $\mathcal {N}$ is called preserving commutativity in both directions if $xy=yx\Leftrightarrow \varphi (x)\varphi (y)=\varphi (y)\varphi (x)$. In this paper, we prove that each invertible linear map on $\mathcal {N}$ preserving commutativity in both directions is exactly a quasi-automorphism of $\mathcal {N}$, and a quasi-automorphism of $\mathcal {N}$ can be decomposed into the product of several standard maps, which extains the main result of Y. Cao, Z. Chen and C. Huang (2002) from fields to rings.
References:
                        
[2] Cao, Y., Chen, Z., Huang, C.: 
Commutativity preserving linear maps and Lie automorphisms of strictly triangular matrix space. Linear Algebra Appl. 350 41-66 (2002). 
MR 1906746 | 
Zbl 1007.15007[3] Cao, Y., Tan, Z.: 
Automorphisms of the Lie algebra of strictly upper triangular matrices over a commutative ring. Linear Algebra Appl. 360 105-122 (2003). 
MR 1948476 | 
Zbl 1015.17017[4] Marcoux, L. W., Sourour, A. R.: 
Commutativity preserving linear maps and Lie automorphisms of triangular matrix algebras. Linear Algebra Appl. 288 89-104 (1999). 
MR 1670535 | 
Zbl 0933.15029[6] Šemrl, P.: 
Non-linear commutativity preserving maps. Acta Sci. Math. 71 781-819 (2005). 
MR 2206609