  Extending the investigations about the theory of duals, we analyze duals
built up with the aid of discrete symmetry operators. We scrutinize algebraic
and physical constraints (encompassing them in a theoretical scope) in order to
verify which combination of discrete symmetries may compose a physical and
mathematical well-posed spinorial dual. In this scenario, we relate the
Lounesto classification with several other spinor classification possibilities,
attempting to connect classes and physical constraints. Several possibilities
are investigated.
