An invariant theoretical description of \(\Lambda \otimes A_*\) (Q910765)

The lambda algebra gives a standard resolution of \({\mathbb{Z}}/2\) over the mod 2 Steenrod algebra. Let \(\Lambda\) be the dual of the lambda algebra and let \(A_*\) be the dual of the mod 2 Steenrod algebra. Then \(\Lambda \otimes A_*\) is a resolution of \({\mathbb{Z}}/2\) by \(A_*\)-comodules. This paper gives a construction of \(\Lambda \otimes A_*\) using invariant theory, similar to that of \textit{W. M. Singer} [Trans. Am. Math. Soc. 280, 673-693 (1983; Zbl 0533.55013)]. In particular, the differential is described in terms of invariant theory.