The Quillen conjecture asserts that contractibility of the order complex of the nonidentity elementary
Abelian p-subgroups of a finite
group
implies a nontrivial normal p-subgroup. Here
is prime,
is ordered by inclusion, and its 0-dimensional simplices
correspond to subgroups isomorphic
to
with
.
Writing
for the largest normal p-subgroup, the implication
is
The converse holds as well.