INVARIANCE AND LOCALIZATION FOR CYCLIC HOMOLOGY OF DG ALGEBRAS

Bernhard Keller

February 11, 1996

Journal of Pure and Applied Algebra, 123 (1998), 223-273.

Abstract. We show that two flat differential graded algebras whose derived categories are equivalent by a derived functor have isomorphic cyclic homology. In particular, `ordinary' algebras over a field which are derived equivalent (J. Rickard) share their cyclic homology, and iterated tilting (Brenner-Butler, Happel-Ringel, Bongartz) preserves cyclic homology. This completes results of J. Rickard's and D. Happel's. It also extends well known results on preservation of cyclic homology under Morita equivalence due to A. Connes, Loday-Quillen, Chr. Kassel, and R. McCarthy. We then show that under suitable flatness hypotheses, an exact sequence of derived categories of DG algebras yields a long exact sequence in cyclic homology. This may be viewed as an analogue of Thomason-Trobaugh's and Yao's localization theorems in K-theory (cf. also Weibel-Yao). I thank the referee for his very careful reading of the manuscript.
http://www.math.jussieu.fr/~keller/publ/ilcabs.html
Bernhard Keller, le 11 février, 1996.
keller@math.jussieu.fr

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