A pro- group, for a fixed prime
,
is a topological group isomorphic to an inverse
limit of finite
-groups. It is a profinite group
whose continuous finite quotient groups all have order
a power of
. The additive group
is an example. For a profinite
group
, its maximal pro-
quotient is the quotient through which every continuous homomorphism
from
to a pro-
group factors.
In the Bogomolov-Pop conjecture, a prime different from the field
characteristic is fixed and the maximal pro-
absolute Galois group
retains field information after further passage to its
abelian-by-central quotient.