\documentclass[12pt]{article} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsmath} \topmargin=0.0in \textwidth=6.5in \textheight=8.5in \oddsidemargin=0.0in \parindent=0.0in \font\bigboldfont=cmbx10 scaled \magstep4 \begin{document} \begin{titlepage} \begin{center} {\bigboldfont Harvard-M.I.T. Algebraic Geometry Seminar} \vspace{0.5in} {\large \bf %%% title goes here in all caps K-THEORY OF A HENSELIAN DISCRETE VALUATION FIELD WITH NON-PERFECT RESIDUE FIELD } \vspace{0.5in} \begin{large} %%% Speaker in caps, school in lower case {\bf LARS HESSELHOLT } Massachusetts Institute of Technology \end{large} \vspace{0.5in} %%% Abstract goes here; comment out otherwise {\bf \textsc{Abstract:} } \end{center} \newcommand{\Fp}{\mathbb{F}_p} \newcommand{\Z}{\mathbb{Z}} \newcommand{\xto}{\xrightarrow} Twenty-five years ago, Bloch introduced the complex of $p$-typical curves on Quillen's algebraic $K$-groups for the purpose of calculating crystalline cohomology. This lead Deligne and Illusie to define the de~Rham-Witt complex, which gives crystalline cohomology. I have showed that for a regular scheme over $\Fp$, the two complexes, in fact, are isomorphic. Both complexes can be defined also for schemes over a discrete valuation ring $V$ of mixed characteristic. And in this case, they are not the same. In this talk, I will explain the structure of the two complexes for a smooth $V$-scheme $X$. Let me just mention here that the Frobenius fixed set of the de~Rham-Witt complex (modulo $p$) is isomorphic to the sheaf of $p$-adic vanishing cycles. The calculation of Bloch's $p$-typical curves in the mixed characteristic setting has the following consequence for algebraic $K$-theory (whence the title): Let $K$ be the quotient field of the henselian local ring of $X$ at the generic point of the special fiber. Then, assuming that $\mu_p\subset K$, there is a canonical isomorphism $$K_*^M(K)\otimes_{\Z}S_{\Z/p}(\mu_p) \xto{\sim} K_*(K,\Z/p),$$ which to $\zeta\in\mu_p$ assigns the corresponding Bott element $b_{\zeta}\in K_2(K,\Z/p)$. This is the value of the $K$-groups predicted by the Beilinson-Licthenbaum conjectures. \vfill %%% Date goes here, and location (Harvard Rm 507 or MIT Room 4--163) \begin{center} {\large April 9, 2002 3:00 p.m. %Harvard Room 507 MIT Room 4-163 } \end{center} \vspace{0.5in} \begin{center} %%% Seminar website goes here \verb+http://www-math.mit.edu/~abuch/seminar/+ \end{center} \end{titlepage} \end{document}