Consider the evaluation map S1times[S1,K(Z,n)]toK(Z,n). Since S1 is a K(Z,1), and [S1,K(Z,n)]=Omega1(K(Z,n)) is a K(Z,n−1), up to homotopy we get a map K(Z,1)timesK(Z,n−1)toK(Z,n). I'm not actually sure if this induces the product on cohomology. If it does, there is a natural generalization:
Consider the space of pointed maps [K(A,n),K(A,m+n)]. Then pik([K(A,n),K(A,m+n)])=0 for k>m, and =A for k=m. To see this, note
that (all maps are pointed)
[Sk,[K(A,n),K(A,m+n)]]=[K(A,n),Omegak(K(A,m+n))]
=[K(A,n),K(A,m+n−k)]=checkHm+n−k(K(A,n),A)=0
if k>m, and =A if k=m (by Hurewicz).
Thus, we have a map i:K(A,m)to[K(A,n),K(A,m+n)] by obstruction theory sending pim(K(A,m))topim([K(A,n),K(A,m+n)]) isomorphically, which of course is equivalent to a map (by evaluation)
K(A,m)timesK(A,n)toK(A,m+n).
Maybe someone could explain to me if this gives the correct cohomology operation?
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