Abstract
We study certain aspects of the algebraic K-theory of Hopf–Galois extensions. We show that the Cartan map from K-theory to G-theory of such an extension is a rational isomorphism, provided the ring of coinvariants is regular, the Hopf algebra is finite dimensional and its Cartan map is injective in degree zero. This covers the case of a crossed product of a regular ring with a finite group and has an application to the study of Iwasawa modules.
Similar content being viewed by others
References
Ardakov, K., Wadsley, S.J.: K 0 and the dimension filtration for p-torsion Iwasawa modules. In: Proceedings of the London Mathematical Society (2008, in press)
Bass, H.: Algebraic K-Theory. Benjamin, New York (1968)
Cohen, M., Fischman, D., Montgomery, S.: Hopf Galois extensions, smash products, and Morita equivalence. J. Algebra 133(2), 351–372 (1990)
Chase, S.U., Sweedler, M.E.: Hopf algebras and Galois theory. Lecture Notes in Mathematics, vol. 97. Springer (1969)
Curtis, C.W., Reiner, I.: Methods of Representation Theory I. Wiley-Interscience, New York (1981)
Lorenz, M.: Representations of finite dimensional Hopf algebras. J. Algebra 188, 476–505 (1997)
Kreimer, H.F., Takeuchi, M.: Hopf algebras and Galois extensions of an algebra. Indiana Univ. Math. J. 30(5), 675–692 (1981)
McConnell, J.C., Robson, J.C.: Noncommutative Noetherian rings. Revised Edition, AMS Graduate Studies in Mathematics, vol. 30 (2001)
Montgomery, S.: Hopf algebras and their actions on rings. CBMS Conference proceedings, AMS (1993)
Quillen, D.: Higher algebraic K-theory I. Lecture Notes in Mathematics, vol. 341, pp. 85–147. Springer (1973)
Rumynin, D.: Hopf–Galois extensions with central invariants and their geometric properties. Algebra Represent. Theory 1(4), 353–381 (1998)
Serre, J.-P.: Linear representations of finite groups. Graduate Texts in Mathematics, vol. 42. Springer (1977)
Schneider, H.-J.: Representation theory of Hopf Galois extensions. Hopf algebras, Israel J. Math. 72(1–2), 196–231 (1990)
Waldhausen, F.: Algebraic K-Theory of generalized free products, Part 1. The Ann. Math. 2nd Series 108(2), 135–204 (1978)
Author information
Authors and Affiliations
Corresponding author
Additional information
The first author thanks Christ’s College, Cambridge for financial support. The second author was supported by EPSRC research grant EP/C527348/1.
Rights and permissions
About this article
Cite this article
Ardakov, K., Wadsley, S.J. On the Cartan Map for Crossed Products and Hopf–Galois Extensions. Algebr Represent Theor 13, 33–41 (2010). https://doi.org/10.1007/s10468-008-9095-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10468-008-9095-4