Published online by Cambridge University Press: 20 November 2018
If ℭ and ℭ′ are classes of finite abelian groups, we write ℭ + ℭ′ for the smallest class containing the groups of ℭ and of ℭ′. For any positive number r, ℭ < r is the smallest class of abelian groups which contains the groups Zp for all primes p less than r.
Our aim in this paper is to prove the following theorem.
THEOREM. Iƒ ℭ is a class of finite abelian groups and
(i) πi(Y) ∈ℭ for i < n,
(ii) H*(X; Z) is finitely generated,
(iii) Hi(X;Z)∈ ℭ for i > n + k,
Then
This statement contains many of the classical results of homotopy theory: the Hurewicz and Hopf theorems, Serre's (mod ℭ) version of these theorems, and Eilenberg's classification theorem. In fact, these are all contained in the case k = 0.