Embedding theorems for actions on generalized trees, I
arXiv:1003.4652
Abstract
Using suitable deformations of simplicial trees and the duality theory for median sets, we show that every free action on a median set can be extended to a free and transitive one. We also prove that the category of median groups is a reflective full subcategory of the category of free actions on pointed median sets.
32 pages; A more conceptual alternative proof of Theorem 3.1. is given, and two new results (Theorems 4.1. and 5.1.) are proved