  The paper is dedicated to the study of strong duality for a problem of linear
copositive programming.
  Based on the recently introduced concept of the set of normalized immobile
indices, an extended dual problem is deduced. The dual problem satisfies the
strong duality relations and does not require any additional regularity
assumptions such as constraint qualifications. The main difference with the
previously obtained results consists in the fact that now the extended dual
problem uses neither the immobile indices themselves nor the explicit
information about the convex hull of these indices.
  The strong duality formulations presented in the paper have similar structure
and properties as that proposed in the works of M. Ramana, L. Tuncel, and H.
Wolkovicz, for semidefinite programming, but are obtained using different
techniques.
