Hopf invariants for mapping cones
The relative James construction provides a functorial Hopf invariant defined on the
fiber of a pinch map. Here we give a lifting of this Hopf invariant from the fiber of
one pinch map to the fiber of another. An application is made to the study of the
Cohen Moore Neisendorfer splitting of the loops of a Moore space in order to
understand the obstructions that come in the study of the double suspension
conjecture.