On certain twin buildings over tree diagrams

by Bernhard Mühlherr and Hendrik Van Maldeghem

Abstract:
We classify twin buildings over tree diagrams such that all rank $2$ residues ar e either finite Moufang polygons but no octagons, or Moufang polygons associated to the groups $PGL_3$, PSp$_4$ or G$_2$. As a byproduct, we obtain some result s on Moufang sets.

Key words and phrases: Moufang set, Moufang foundation, Steinberg twist, Kac-Moody twin build ings, 2-spherical twin buildings

1991 Mathematics Subject Classification: 51E24.

Published in: Bull. Belg. Math. Soc. 5 (1998), 393-402

Contact: Bernhard.Muehlherr@Mathematik.Uni-Dortmund.DE