## Explicit example showing non-residual finiteness

This is mostly a continuation on the group I gave in the last post, which is given by the presentation $$G = \langle a,t ~|~ t^{-1}a^2t = a^3\rangle.$$ At the risk of beating a dead horse, I proved that the homomorphism $f:G\to G$ given on generators by $f(t) = t$ and $f(a) = a^2$ is […]