A comparison of Hochschild homology in algebraic and smooth settings

Autor: Kazhdan, David, Solleveld, Maarten
Rok vydání: 2022
Předmět:
Druh dokumentu: Working Paper
Popis: Consider a complex affine variety $\tilde V$ and a real analytic Zariski-dense submanifold V of $\tilde V$. We compare modules over the ring $O (\tilde V)$ of regular functions on $\tilde V$ with modules over the ring $C^\infty (V)$ of smooth complex valued functions on V. Under a mild condition on the tangent spaces, we prove that $C^\infty (V)$ is flat as a module over $O (\tilde V)$. From this we deduce a comparison theorem for the Hochschild homology of finite type algebras over $O (\tilde V)$ and the Hochschild homology of similar algebras over $C^\infty (V)$. We also establish versions of these results for functions on $\tilde V$ (resp. V) that are invariant under the action of a finite group G. As an auxiliary result, we show that $C^\infty (V)$ has finite rank as module over $C^\infty (V)^G$.
Comment: V2: compactness assumptions in section 3 lifted. V3: various corrections and improvements in the proofs in sections 1 and 2, new section with examples
Databáze: arXiv