A group $G$ is <residually finite group>[residually finite] when, for every $1\ne g\in G$, there are a <finite group> $Q$ and a <group homomorphism> $q:G\to Q$ such that $q(g)\ne1$. Equivalently, the intersection of all finite-index normal subgroups of $G$ is trivial.

Solution

Past exam of the mathematics course of the University of Cambridge / 2022 / iii / Paper 104 / 4 / a / Solution

 Solution (source code)