Items for "Twin building"

The Thick Frame of a Weak Twin Building

We prove the following extension to twin buildings of a result for spherical buildings which appears in [11]: to every weak twin building ?, there is canonically associated a thick twin building ?? whose Weyl group W (??) can be considered as a reflection subgroup of the Weyl group W(?) of ?; conversely, it is possible to recover ? from the thick twin building ?? and from the inclusion W(??), ? W(?).

Keywords: Twin building, weak building