Fusion system induced by a finite group on its p-Sylow subgroup is the inner fusion system iff the group is p-nilpotent
From Groupprops
Statement
Suppose is a finite group and
is a
-Sylow subgroup of
. Then, the fusion system induced by
on
(i.e.,
) equals the inner fusion system
if and only if
is a P-nilpotent group (?), i.e.,
contains a Normal p-complement (?).
Facts used
Proof
Given: A finite group , a
-Sylow subgroup
of
, such that
.
To prove: has a normal
-complement.
Proof:
- Suppose
are conjugate in
. Then,
are conjugate in
: Let
. Then, if
consider the map
given by
. This is a morphism in
, so it is also a morphism in
. In particular, there exists
such that
.
-
has a normal complement in
, so
has a normal
-complement: This follows from the previous step and fact (1).