Generalized quadrangles with a regular point and association schemes

Dina Ghinelli, Stefan Löwe
1995 Linear Algebra and its Applications  
There is a new method of constructing generalized quadrangles (GQs) which is based on covering of nets; all GQs with a regular point can be represented in this way. Here we first construct from a generalized quadrangle d with a regular point a four-class association scheme .&@'I called in brief geometric. It is then natural to call pseudo-geometric any association scheme M with the same parameters as LX'(@). We use eigenvalue techniques and the above method of construction to give a
more » ... tion of pseudo-geometric association schemes which are geometric.
doi:10.1016/0024-3795(94)00305-w fatcat:4qc2ysz6ofg2lepqobyv2o67pi