Computations of $K_2$ for certain $\mathbb{Z}/p^s\mathbb{Z}$-algebras and the extension of Oliver's logarithm

Fuente: arXiv
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Main Author: Zhang, Yakun
Format: Preprint
Published: 2025
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_version_ 1866908832675921920
author Zhang, Yakun
author_facet Zhang, Yakun
contents This paper describes the $K$-theory structure for three algebra classes. For cyclic $p$-group rings and truncated polynomial rings over $\mathbb{Z}/p^s\mathbb{Z}$, we determine reduced $K_2$-structures via a common algebraic framework. For abelian $p$-group rings over $\widehat{\mathbb{Z}}_p$, we extend the isomorphism between reduced continuous $K_2$ and the first cyclic homology group to all finite abelian $p$-groups. A constructive proof using a generalized Artin-Hasse map yields an explicit splitting. This isomorphism is realized by extending Oliver's $p$-adic logarithm. We also characterize the map from reduced continuous $K_2$ to reduced linearized $K_2$, clarifying the links between $K_2$, cyclic homology, and Kähler differentials.
format Preprint
id arxiv_https___arxiv_org_abs_2503_00773
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Computations of $K_2$ for certain $\mathbb{Z}/p^s\mathbb{Z}$-algebras and the extension of Oliver's logarithm
Zhang, Yakun
K-Theory and Homology
19C20, 16S34, 19D55, 13N05
This paper describes the $K$-theory structure for three algebra classes. For cyclic $p$-group rings and truncated polynomial rings over $\mathbb{Z}/p^s\mathbb{Z}$, we determine reduced $K_2$-structures via a common algebraic framework. For abelian $p$-group rings over $\widehat{\mathbb{Z}}_p$, we extend the isomorphism between reduced continuous $K_2$ and the first cyclic homology group to all finite abelian $p$-groups. A constructive proof using a generalized Artin-Hasse map yields an explicit splitting. This isomorphism is realized by extending Oliver's $p$-adic logarithm. We also characterize the map from reduced continuous $K_2$ to reduced linearized $K_2$, clarifying the links between $K_2$, cyclic homology, and Kähler differentials.
title Computations of $K_2$ for certain $\mathbb{Z}/p^s\mathbb{Z}$-algebras and the extension of Oliver's logarithm
topic K-Theory and Homology
19C20, 16S34, 19D55, 13N05
url https://arxiv.org/abs/2503.00773