The Ghinelli--Löwe construction of generalized quadrangles (Q1399687)

The authors dig up an old construction of some finite generalized quadrangles due to Ghinelli and Löwe, which was never published. No new examples arise, but the authors identify earlier examples of this method (and these examples were not identified before) as flock quadrangles of Cantor-Knuth type. A crucial argument is a beautiful theorem by Thas that guarantees a quadrangle to be a flock quadrangle if Property (G) holds at a point [\textit{J. A. Thas}, J. Comb. Theory, Ser. A 87, 247-272 (1999; Zbl 0949.51003)].