EN
The paper is devoted to generalizations of the Cencelj-Dranishnikov theorems relating extension properties of nilpotent CW complexes to their homology groups. Here are the main results of the paper:
Theorem 0.1. Let L be a nilpotent CW complex and F the homotopy fiber of the inclusion i of L into its infinite symmetric product SP(L). If X is a metrizable space such that $XτK(H_{k}(L),k)$ for all k ≥ 1, then $XτK(π_{k}(F),k)$ and $XτK(π_{k}(L),k)$ for all k ≥ $.
Theorem 0.2. Let X be a metrizable space such that dim(X) < ∞ or X ∈ ANR. Suppose L is a nilpotent CW complex. If XτSP(L), then XτL in the following cases:
(a) H₁(L) is finitely generated.
(b) H₁(L) is a torsion group.