How many subgroups with index two are there of a free group on two generators? What are their generators?
All I know is that the subgroups should have $(2 \times 2) + 1 - 2 = 3$ generators.
How many subgroups with index two are there of a free group on two generators? What are their generators?
All I know is that the subgroups should have $(2 \times 2) + 1 - 2 = 3$ generators.