A torsion-free abelian group
A is
orderable, i.e. there is a linear order < on
A such that if
g <
h then
g +
k <
h +
k for all
g,
h,
k in
A. The question is whether Suslin lines or Aronszajn lines can ever be orderings of abelian groups. See
http://mathoverflow.net/questions/179618/can-suslin-lines-ever-be-orderings-of-abelian-groups