Twisted conjugacy in classical groups over certain domains of Characteristic $p>0$

Abstract: Let $F$ be a subfield of the algebraic closure of a finite field $\mathbb{F}p$, $p \ne 2$, and let $R$ denote any ring such that $F[t] \subset R \subsetneq F(t)$. Let $G$ be a classical Chevalley group of adjoint type defined over $R$. We prove that the group $G(R)$ has the $R{\infty}$-property.