A functorial property of nested Witt vectors (Q1849105): Difference between revisions

In 1997, \textit{L. Roberts} [Queen's Pap. Pure Appl. Math. 105, 2-36 (1997)] published a paper on the ring of Witt vectors. The author of the paper under review points out that from the Roberts' paper one can extract the following result. Let \(p\) be a prime number, \(M=\{1,p,p^2,\dots\}\) and \(N\subset \mathbb{N}\) the set of natural numbers coprime to \(p.\) Then for any commutative algebra \(A\) there is a functorial isomorphism of rings of Witt vectors \(W_N(W_M(A))\cong W_N(A)\). The aim of the paper is to generalize this result to the case of any coprime truncation sets \(M,N\subset \mathbb{N}.\)