Published online by Cambridge University Press: 20 November 2018
It is known [4] that the finite two- dimensional unitary group U(2,
p2n) is generated by two reflections if p ≠ 2. The present
note completes that result by giving two generating reflections for U(2,
22n), n > 1. As in [4] this implies that the points of the
"unit circle " in the
unitary plane over GF(22n), n > 1, are the vertices of a
"regular unitary polygon" whose group of auto- 2n morphisms is U(2,
22n).
The final section gives abstract definitions for the particular groups U(2,24) and U(2,52) in terms of their generating reflections.