Hughes plane

In mathematics, a Hughes plane is one of the non-Desarguesian projective planes found by. There are examples of order p2n for every odd prime p and every positive integer n.

Construction
The construction of a Hughes plane is based on a nearfield N of order p2n for p an odd prime whose kernel K has order pn and coincides with the center of N.

Properties
A Hughes plane H:
 * 1) is a non-Desarguesian projective plane of odd square prime power order of Lenz-Barlotti type I.1,
 * 2) has a Desarguesian Baer subplane H0,
 * 3) is a self-dual plane in which every orthogonal polarity of H0 can be extended to a polarity of H,
 * 4) every central collineation of H0 extends to a central collineation of H, and
 * 5) the full collineation group of H has two point orbits (one of which is H0), two line orbits, and four flag orbits.

The smallest Hughes Plane (order 9)
The Hughes plane of order 9 was actually found earlier by Veblen and Wedderburn in 1907. A construction of this plane can be found in where it is called the plane Ψ.