Directed power graph-equivalent not implies 1-isomorphic for infinite groups
Statement
It is possible to have two infinite groups and that are directed power graph-equivalent (i.e., they have isomorphic directed power graphs) and are not 1-isomorphic groups (?).
Related facts
- Finite groups are 1-isomorphic iff their directed power graphs are isomorphic
- Undirected power graph determines directed power graph for finite group
Proof
For any prime , consider the group of rational numbers that, in reduced form, have denominator a power of . The isomorphism class of the directed power graph of is independent of .