Two methods, one algebraic and one geometric, are given to determine the
autotopism group of the commutative Dickson semifield, completing a result of
Sandler. The collineation stabilizer subgroup of the embedded Ganley unital is
exhibited as a semidirect product whose factor groups are semidirect products of
abelian groups.
Keywords
Dickson semifield, semifield plane, autotopism group,
stabilizer of the embedded Ganley unital, automorphism
group of unitary block design, inversive plane
