We study the nested collection of left ideals of A, the mod 2 Steenrod algebra, L(k):=A{Sq20, Sq21, Sq22, ..., Sq2k}. We determine the smallest k such that Sqn ∈ L(k).
We discuss an application which improves upon the results of F. R. Cohen and the first author in their paper comparing the loop of the degree 2 map on a sphere and the H-space squaring map on the loop of a sphere.Homology, Homotopy and Applications, Vol. 9 (2007), No. 1, pp.185-191.