Borger, James2015-12-071937-0652http://hdl.handle.net/1885/20650We give a concrete description of the category of étale algebras over the ring of Witt vectors of a given finite length with entries in an arbitrary ring. We do this not only for the classical p-typical and big Witt vector functors but also for certain aAuthor/s retain copyrightKeywords: Frobenius lift; Lambda-ring; Plethory; Witt space; Witt vector201110.2140/ant.2011.5.2312016-02-24