The fibre of the degree 3 map, Anick spaces and the double suspension

Let S2n+1{p} denote the homotopy fibre of the degree p self map of S2n+1. For primes p ≥ 5, work by Selick shows that S2n+1{p} admits a non-trivial loop space decomposition if and only if n = 1 or p. Indecomposability in all but these dimensions was obtained by showing that a non-trivial decomposition of ΩS2n+1{p} implies the existence of a p-primary Kervaire invariant one element of order p in $\pi _{2n(p-1)-2}^S$. We prove the converse of this last implication and observe that the homotopy decomposition problem for ΩS2n+1{p} is equivalent to the strong p-primary Kervaire invariant problem for all odd primes. For p = 3, we use the 3-primary Kervaire invariant element θ3 to give a new decomposition of ΩS55{3} analogous to Selick's decomposition of ΩS2p+1{p} and as an application prove two new cases of a long-standing conjecture stating that the fibre of the double suspension $S^{2n-1} \longrightarrow \Omega ^2S^{2n+1}$ is homotopy equivalent to the double loop space of Anick's space.

Attaching cells to finite complexes, with an application to elliptic spaces

Suppose that f; Sn → E is a continuous map from the n-sphere to a 1-connected CW complex E, with n ≥ 2. One may suppose that f is a cofibration, so that there is a cofibration sequence , with f the attaching map of the cell en+1. Consider the homotopy fibre F of the inclusion E ↪ B, so that there is a homotopy fibration let δ; ΩB → F be the connectant of this fibration. The following definition is given by Félix and Lemaire in [11]: Definition 1·1. Suppose that k is a field of characteristic p ≥ 0. The attaching map f:Sn → E is: 1. p-inert if is surjective; 2. p-lazy if is zero; where H˜ denotes reduced homology and coefficients are taken in the field k.

The fibre of a cell attachment

In view of understanding the Hopf algebra structure of the loop space homology in terms of H*(ΩE) and the map f, we consider the homotopy fibre F of the inclusion map In [15], the case when H*(Ωω) is surjective (the “inert” case) was studied, and in [11] a weaker condition, called “lazy”, was considered. Here we give several new characterizations of inert and lazy cell attachments in terms of properties of F. We also show how these results extend to the case of the mapping cone of an arbitrary map f: W→E.