  Stability conditions on triangulated categories were introduced by Bridgeland
as a 'continuous' generalisation of t-structures. The set of locally-finite
stability conditions on a triangulated category is a manifold which has been
studied intensively.
  However, there are mainstream triangulated categories whose stability
manifold is the empty set. One example is the compact derived category of the
dual numbers over an algebraically closed field.
  This is one of the motivations in this paper for introducing co-stability
conditions as a 'continuous' generalisation of co-t-structures. Our main result
is that the set of nice co-stability conditions on a triangulated category is a
manifold. In particular, we show that the co-stability manifold of the compact
derived category of the dual numbers is the complex numbers.
