The Theory of Witt Vectors
arXiv:1409.7445
Abstract
This is an introduction to the theory of Witt vectors. It includes a construction of the Witt rings, the Frobenius and Verschiebung endomorphisms, the canonical map from W to W^2 (its lambda-algebra structure), the relation to strict p-rings, and an account of the Artin-Hasse exponential.
28 pages. Written in 2007 and posted unmodified to the arXiv by request