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Noncommutative motives of Azumaya algebras

Published online by Cambridge University Press:  10 March 2014

Gonçalo Tabuada
Affiliation:
Department of Mathematics, MIT, Cambridge, MA 02139, USA Departamento de Matemática e CMA, FCT-UNL, Quinta da Torre, 2829-516 Caparica, Portugal ([email protected]) http://math.mit.edu/∼tabuada
Michel Van den Bergh
Affiliation:
Departement WNI, Universiteit Hasselt, 3590 Diepenbeek, Belgium ([email protected]) http://hardy.uhasselt.be/personal/vdbergh/Members/∼michelid.html

Abstract

Let $k$ be a base commutative ring, $R$ a commutative ring of coefficients, $X$ a quasi-compact quasi-separated $k$-scheme, and $A$ a sheaf of Azumaya algebras over $X$ of rank $r$. Under the assumption that $1/r\in R$, we prove that the noncommutative motives with $R$-coefficients of $X$ and $A$ are isomorphic. As an application, we conclude that a similar isomorphism holds for every $R$-linear additive invariant. This leads to several computations. Along the way we show that, in the case of finite-dimensional algebras of finite global dimension, all additive invariants are nilinvariant.

Type
Research Article
Copyright
© Cambridge University Press 2014 

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