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arXiv · 2401.03112

Certain functional identities on division rings

Tsiu-Kwen Lee·Jheng-Huei Lin
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Abstract

We study the functional identity $G(x)f(x)=H(x)$ on a division ring $D$, where $f \colon D\to D$ is an additive map and $G(X)\ne 0, H(X)$ are generalized polynomials in the variable $X$ with coefficients in $D$. Precisely, it is proved that either $D$ is finite-dimensional over its center or $f$ is an elementary operator. Applying the result and its consequences, we prove that if $D$ is a noncommutative division ring of characteristic not $2$, then the only solution of additive maps $f, g$ on $D$ satisfying the identity $f(x) = x^n g(x^{-1})$ with $n\ne 2$ a positive integer is the trivial case, that is, $f=0$ and $g=0$. This extends Catalano and Merchán's result in 2023 to get a complete solution.

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Tsiu-Kwen Lee, Jheng-Huei Lin. 2024-01-06. Certain functional identities on division rings. https://doi.org/10.1016/j.jalgebra.2024.03.002

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