Residual finiteness of infinite amalgamated products of cyclic groups.
The authors show a necessary and sufficient condition for the fundamental group \(\pi_1(\Gamma,X)\) of a graph of groups \((\Gamma,X)\) to be residually finite. The main theorem completely classifies \(\pi_1(\Gamma,X)\) as far as residual finiteness is concerned. They also classify the residual finiteness and the subgroup separability of the subgroups of \((\mathbb{Q},+)\), the additive group of rationals.
scientific article; zbMATH DE number 5083183