Unstable algebras over an operad II

Abstract

$\def\P\{\mathcal{P}}$We work over the finite field $\mathbb{F}_q$. We introduce a notion of unstable $\P$-algebra over an operad $\P$. We show that the unstable $\P$-algebra freely generated by an unstable module is itself a free $\P$-algebra under suitable conditions. We introduce a family of ‘$q$-level’ operads which allows us to identify unstable modules studied by Brown–Gitler, Miller and Carlsson in terms of free unstable $q$-level algebras.