Additive Ternary $Γ$-Modules and Homological Algebra

Fuente: arXiv
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Autores principales: Gokavarapu, Chandrasekhar, Dasari, Madhusudhana Rao
Formato: Preprint
Publicado: 2025
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author Gokavarapu, Chandrasekhar
Dasari, Madhusudhana Rao
author_facet Gokavarapu, Chandrasekhar
Dasari, Madhusudhana Rao
contents Fix a commutative monoid $(T,+,0)$, a commutative monoid $(Γ,+,0_Γ)$, and a map \[ (a,α,b,β,c)\longmapsto a\,α\,b\,β\,c\in T \] which is additive in each variable and associative in the ternary sense. A left additive ternary $Γ$-module is an abelian group $M$ equipped with an action $(a,α,b,β,m)\mapsto a\,α\,b\,β\,m$ satisfying the same associativity constraints. Two scalars are intrinsic, so the action is genuinely polyadic; in particular, we do not assume a canonical unary action $T\times M\to M$. The first part constructs the \emph{operator ring} $\mathcal O_{T,Γ}$ generated by the left translations $(a,α,b,β)$. It is shown that $T\!\!\;\!-\!Γ\mathrm{Mod}$ is equivalent to the ordinary module category $\mathcal O_{T,Γ}\mathrm{Mod}$. The category is therefore abelian. Under the unital operator hypothesis \emph{(U)} (i.e. when $\mathcal O_{T,Γ}$ is unital), it has enough projectives and enough injectives. The second part defines a tensor product over $T$ by a \emph{bi-balanced} universal property forced by the ternary action, proves right exactness of $-\otimes_T-$, and establishes a Tensor--Hom adjunction for bimodules. Assuming \emph{(U)}, derived functors $\mathrm{Ext}$ and $\mathrm{Tor}$ are developed inside the additive track. A finite example with $T=\ZZ/4\ZZ$ gives explicit computations \[\mathrm{Ext}^1_T(\ZZ/2\ZZ,\ZZ/2\ZZ)\cong \ZZ/2\ZZ,\qquad \mathrm{Tor}^T_1(\ZZ/2\ZZ,\ZZ/2\ZZ)\cong \ZZ/2\ZZ,\] with a concrete nonsplit extension and an explicit failure of tensor exactness. Counterexamples isolate the precise points where naive binary-module arguments break.
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publishDate 2025
record_format arxiv
spellingShingle Additive Ternary $Γ$-Modules and Homological Algebra
Gokavarapu, Chandrasekhar
Dasari, Madhusudhana Rao
Rings and Algebras
Primary 16Y60, Secondary 18G15, 16D90, 18E10
Fix a commutative monoid $(T,+,0)$, a commutative monoid $(Γ,+,0_Γ)$, and a map \[ (a,α,b,β,c)\longmapsto a\,α\,b\,β\,c\in T \] which is additive in each variable and associative in the ternary sense. A left additive ternary $Γ$-module is an abelian group $M$ equipped with an action $(a,α,b,β,m)\mapsto a\,α\,b\,β\,m$ satisfying the same associativity constraints. Two scalars are intrinsic, so the action is genuinely polyadic; in particular, we do not assume a canonical unary action $T\times M\to M$. The first part constructs the \emph{operator ring} $\mathcal O_{T,Γ}$ generated by the left translations $(a,α,b,β)$. It is shown that $T\!\!\;\!-\!Γ\mathrm{Mod}$ is equivalent to the ordinary module category $\mathcal O_{T,Γ}\mathrm{Mod}$. The category is therefore abelian. Under the unital operator hypothesis \emph{(U)} (i.e. when $\mathcal O_{T,Γ}$ is unital), it has enough projectives and enough injectives. The second part defines a tensor product over $T$ by a \emph{bi-balanced} universal property forced by the ternary action, proves right exactness of $-\otimes_T-$, and establishes a Tensor--Hom adjunction for bimodules. Assuming \emph{(U)}, derived functors $\mathrm{Ext}$ and $\mathrm{Tor}$ are developed inside the additive track. A finite example with $T=\ZZ/4\ZZ$ gives explicit computations \[\mathrm{Ext}^1_T(\ZZ/2\ZZ,\ZZ/2\ZZ)\cong \ZZ/2\ZZ,\qquad \mathrm{Tor}^T_1(\ZZ/2\ZZ,\ZZ/2\ZZ)\cong \ZZ/2\ZZ,\] with a concrete nonsplit extension and an explicit failure of tensor exactness. Counterexamples isolate the precise points where naive binary-module arguments break.
title Additive Ternary $Γ$-Modules and Homological Algebra
topic Rings and Algebras
Primary 16Y60, Secondary 18G15, 16D90, 18E10
url https://arxiv.org/abs/2511.02544