Category and generalized Hopf invariants
Israel Berstein, P. J. Hilton · Illinois Journal of Mathematics · 1960
I. BERSTEIN AND P. J. HIITON '(ZA, Y) --+ r(ZA, T'(Y) as in 2.8.Although in general fails to be a homomorphism, it retains the property j. 1.As observed by Puppe [8], there is an operation of (2A, Z) on (Y, Z)