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Balint Rago

Publications and source records attributed to Balint Rago.

7 recordsLinked to original sources
arXiv2026

The isomorphism problem for reduced finitary power monoids

Let $H$ be a multiplicatively written monoid with identity $1_H$ and let $\mathcal{P}_{\text{fin},1}(H)$ denote the reduced finitary power monoid of $H$, that is, the monoid consisting of all finite subsets of $H$ containing $1_H$ with set multiplication as operation. Building on work of Tringali and Yan, we give a complete description of pairs of commutative and cancellative monoids $H,K$ for which $\mathcal{P}_{\text{fin},1}(H)$ and $\mathcal{P}_{\text{fin},1}(K)$ are isomorphic.

math.CO↗
arXiv2025

The automorphism group of reduced power monoids of finite abelian groups

Let $H$ be an additively written monoid and let $\mathcal{P}_{0}(H)$ denote the reduced power monoid of $H$, that is, the monoid consisting of all subsets of $H$ containing $0$ with set addition as operation. Following work of Tringali, Wen and Yan, we give a full description of the automorphism group of $\mathcal{P}_{0}(G)$, where $G$ is a finite abelian group. More precisely, we show that $\text{Aut}(\mathcal{P}_{0}(G))$ and $\text{Aut}(G)$ are isomorphic in a canonic way, except in the special case when $G$ is isomorphic to the Klein four-group.

math.CO↗
arXiv2025

A counterexample to an isomorphism problem for power monoids

Let $H$ be a (multiplicatively written) monoid. The family $\mathcal{P}_{\text{fin},1}(H)$ of finite subsets of $H$ containing the identity element is itself a monoid when endowed with setwise multiplication induced by $H$. Tringali and Yan proved that two monoids $H_1$ and $H_2$ contained in a special class of commutative, cancellative monoids are isomorphic if and only if $\mathcal{P}_{\text{fin},1}(H_1)$ and $\mathcal{P}_{\text{fin},1}(H_2)$ are. Moreover, they raised the question whether the same holds in the general setting of cancellative monoids. We show that if $H_1$ and $H_2$ are (commutative) valuation monoids with trivial unit groups and isomorphic quotient groups, then $\mathcal{P}_{\text{fin},1}(H_1)\simeq\mathcal{P}_{\text{fin},1}(H_2)$. This provides a negative answer to Tringali and Yans question already within the class of valuation submonoids of the additive group $\mathbb{Z}^2$.

math.AC↗
arXiv2024

A characterization of transfer Krull orders in Dedekind domains with torsion class group

We establish a characterization (under some natural conditions) of those orders in Dedekind domains which allow a transfer homomorphism to a monoid of zero-sum sequences. As a consequence, the inclusion map to the Dedekind domain is a transfer homomorphism, with the exception of a particular case. The arithmetic of Krull and Dedekind domains is well understood, and the existence of a transfer homomorphism implies that the order and the associated Dedekind domain share the same arithmetic properties. This is not the case for arbitrary orders in Dedekind domains.

math.AC↗
arXiv2024

A realization theorem for almost Dedekind domains

An integral domain $D$ is called an SP-domain if every ideal is a product of radical ideals. Such domains are always almost Dedekind domains, but not every almost Dedekind domain is an SP-domain. The SP-rank of $D$ provides a natural measure of the deviation of $D$ from being an SP-domain. In the present paper we show that every ordinal number $\alpha$ can be realized as the SP-rank of an almost Dedekind domain.

math.AC↗
arXiv2024

The ramification tree and almost Dedekind domains of prescribed SP-rank

Given a valuation $v$ with quotient field $K$ and a sequence $\mathcal{K} :K_0\subseteq K_1\subseteq\cdots$ of finite extensions of $K$, we construct a weighted tree $\mathcal{T}(v,\mathcal{K})$ encoding information about the ramification of $v$ in the extensions $K_i$; conversely, we show that a weighted tree $\mathcal{T}$ can be expressed as $\mathcal{T}(v,\mathcal{K})$ under some mild hypothesis on $v$ or on $\mathcal{T}$. We use this construction to construct, for every countable successor ordinal number $\alpha$, an almost Dedekind domain $D$, integral over $V$ (the valuation domain of $v$) whose SP-rank is $\alpha$. Subsequently, we extend this result to countable limit ordinal numbers by considering integral extensions of Dedekind domains with countably many maximal ideals.

math.AC↗