English

Cyclic homology of commutative algebras over general ground rings

K-Theory and Homology 2011-08-29 v1

Abstract

We consider commutative algebras and chain DG algebras over a fixed commutative ground ring kk as in the title. We are concerned with the problem of computing the cyclic (and Hochschild) homology of such algebras via free DG-resolutions ΛV@>>>A\Lambda V @>>> A. We find spectral sequences Ep,q2=Hp(ΛVΓq(dV))HHp+q(ΛV)E^2_{p,q}=H_p(\Lambda V\otimes\Gamma^q(dV))\Rightarrow HH_{p+q}(\Lambda V) and E\pq2=Hp(ΛVΓq(dV))HCp+q(ΛV){E'}^2_{\pq}=H_p(\Lambda V\otimes\Gamma^{\le q}(dV)) \Rightarrow HC_{p+q}(\Lambda V) The algebra ΛVΓ(dV)\Lambda V\otimes\Gamma(dV) is a divided power version of the de Rham algebra; in the particular case when kk is a field of characteristic zero, the spectral sequences above agree with those found by Burghelea and Vigu\'e (Cyclic homology of commutative algebras I, Lecture Notes in Math. {\bf 1318} (1988) 51-72), where it is shown they degenerate at the E2E^2 term. For arbitrary ground rings we prove here (Theorem 2.3) that if Vn=0V_n=0 for n2n\ge 2 then E2=EE^2=E^\infty. From this we derive a formula for the Hochschild homology of flat complete intersections in terms of a filtration of the complex for crystalline cohomology, and find a description of E2{E'}^2 also in terms of crystalline cohomology (theorem 3.0). The latter spectral sequence degenerates for complete intersections of embedding dimension 2\le 2 (Corollary 3.1). Without flatness assumptions, our results can be viewed as the computation Shukla (cyclic) homology (T. Pirashvili, F. Waldhausen; Mac Lane homology and topological Hochschild homology, J. Pure Appl. Algebra{\bf 82} (1992) 81-98).

Keywords

Cite

@article{arxiv.math/0001145,
  title  = {Cyclic homology of commutative algebras over general ground rings},
  author = {Guillermo Cortiñas},
  journal= {arXiv preprint arXiv:math/0001145},
  year   = {2011}
}

Comments

10 pages, AmsTex