RUS  ENG
Full version
JOURNALS // Vestnik Tomskogo Gosudarstvennogo Universiteta. Matematika i Mekhanika // Archive

Vestn. Tomsk. Gos. Univ. Mat. Mekh., 2014 Number 5(31), Pages 16–29 (Mi vtgu412)

MATHEMATICS

Correctness of Abelian torsion-free groups and determinability of Abelian groups by their subgroups

S. Ya. Grinshpona, A. K. Mordovskoib

a Tomsk State University, Tomsk, Russian Federation
b Buryat State University, Ulan-Ude, Russian Federation

Abstract: An Abelian group $A$ is called correct if for any Abelian group $B$ isomorphisms $A\cong B'$ and $B\cong A'$, where $A'$ and $B'$ are subgroups of the groups $A$ and $B$, respectively, imply the isomorphism $A\cong B$. We say that a group $A$ is determined by its subgroups (its proper subgroups) if for any group $B$ the existence of a bijection between the sets of all subgroups (all proper subgroups) of groups $A$ and $B$ such that corresponding subgroups are isomorphic implies $A\cong B$.
In this paper, connections between the correctness of Abelian groups and their determinability by their subgroups (their proper subgroups) are established. Certain criteria of determinability of divisible torsion-free groups and completely decomposable groups by their subgroups and their proper subgroups, as well as a criterion of correctness of such groups, are obtained.

Keywords: almost isomorphism, $s$-isomorphism, $t$-isomorphism, correctness of Abelian groups, determinability of Abelian groups by their subgroups (their proper subgroups).

UDC: 512.541

Received: 21.05.2014



© Steklov Math. Inst. of RAS, 2024