Chapter Eleven

Moufang Quadrangles

1 A generalized n-gon is called a generalized triangle if , a generalized quadrangle if , etc. A generalized n-gon is also called simply a generalized polygon if there is no need to specify n. The notion of a generalized n-gon with is equivalent to the notion of an irreducible spherical building of rank two; see, for instance, [13].

2 That is, of quadratic form type defined by an anisotropic quadratic space which is degenerate.