The automorphism group
of a compact topological projective plane with an
-dimensional
point space is a locally compact group. If the dimension of
is at
least
,
then
is known to be a Lie group. For the connected
component
of
it is
shown that
suffices, if
is semisimple or does not fix exactly a nonincident point-line pair or a double-flag.
is also a Lie group,
if
has a compact
connected
-dimensional
normal subgroup and
.