Orderable groups and bundles
  We define what is meant by a strict total order in a category having subobjects, products and fibre products. This allows us to define the notions of an ordered bundle X and an ordered G-set; when G=\pi_1(X) we relate these structures to orderings of \pi_1(X). We apply this to prove a theorem of Farrell relating right-orderings of \pi_1(X) to embeddings of the universal cover into line bundles over X, and generalize it by relating bi-orderings of \pi_1(X) to embeddings of the path space into line bundles over X \times X. 
Mathieu Anel and Adam Clay
math.AT math.GR