# Lie powers and Witt vectors

Bryant, R. M. and Johnson, Marianne (2008) Lie powers and Witt vectors. Journal of Algebraic Combinatorics. ISSN 0925-9899 (In Press)

In the study of Lie powers of a module $V$ in prime characteristic $p$, a basic role is played by certain modules $B_n$ introduced by Bryant and Schocker. The isomorphism types of the $B_n$ are not fully understood, but these modules fall into infinite families $\{ B_k, B_{pk}, B_{p^2 k}, \dots \}$, one family $B(k)$ for each positive integer $k$ not divisible by $p$, and there is a recursive formula for the modules within $B(k)$. Here we use combinatorial methods and Witt vectors to show that each module in $B(k)$ is isomorphic to a direct sum of tensor products of direct summands of the $k$th tensor power $V^{\otimes k}$.