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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2019 Volume 484, Pages 72–85 (Mi znsl6859)

Mod-$2$ (co)homology of an abelian group

S. O. Ivanova, A. A. Zaikovskiiab

a Laboratory of Modern Algebra and Applications, St. Petersburg State University, 14th Line, 29b, St. Petersburg, 199178 Russia
b St. Petersburg Department of Steklov Mathematical Institute

Abstract: It is known that for a prime $p\ne 2$ there is the following natural description of the homology algebra of an abelian group $H_*(A,\mathbb F_p)\cong \Lambda(A/p)\otimes \Gamma({}_pA)$ and for finitely generated abelian groups there is the following description of the cohomology algebra of $H^*(A,\mathbb F_p)\cong \Lambda((A/p)^\vee)\otimes \mathsf{Sym}(({}_pA)^\vee).$ We prove that there are no such descriptions for $p=2$ that “depend” only on $A/2$ and ${}_2A$ but we provide natural descriptions of $H_*(A,\mathbb F_2)$ and $H^*(A,\mathbb F_2)$ that “depend” on $A/2,$ ${}_2A$ and a linear map $\widetilde \beta\colon {}_2A\to A/2.$ Moreover, we prove that there is a filtration by subfunctors on $H_n(A,\mathbb F_2)$ whose quotients are $\Lambda^{n-2i}(A/2)\otimes \Gamma^i({}_2A)$ and that for finitely generated abelian groups there is a natural filtration on $H^n(A,\mathbb F_2)$ whose quotients are $ \Lambda^{n-2i}((A/2)^\vee)\otimes \mathsf{Sym}^i(({}_2A)^\vee).$

Key words and phrases: homological algebra, algebraic topology, abelian group homology, Eilenberg–MacLane space, Hopf algebra, divided power algebra.

UDC: 515.146.36

Received: 11.09.2019

Language: English



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