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Stefan Kohl
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Zariski dense subgroups of linear algebraic groups

The theorem of Matthews, Verenstein and Weisfeiler asserts that if $G$ is a simply connected absolutely almost simple groups over $Q$ and $\Gamma$ a finitely generated subgroup of $G(Q)$ which is Zariski dense in $G$ then for almost all primes $p$, the reduction of $\Gamma$ mod $p$ is $G_p(F_p)$.

I was wondering wether the assumption `absolutely almost simple' is really necessary? For example, would the conclusion hold for a group like $Res_{F/Q} G$ where $F$ is a number field and $G$ absolutely simple simply connected over $F$?