Based on Greig and Carmichael.
The geometries examined are the finite projective geometries PG(k,qρν), where k is the dimension of the geometry, q is a prime number, and ρ, ν are positive integers. The geometries contain within them sub-geometries PG(k,qν). From this structure can be derived classes of the points and lines (and of planes etc, but these are not the major current interest). The initial geometries are BIBDs, but by deleting various classes of points and/or lines, various other designs can be obtained.
The terminology for these classes is in some parts based on Greig's, in others on Carmichael's.
Last Updated on 1/10/2005
By D.H.Rees