Finite index supergroups and subgroups of torsionfree abelian groups of rank two (CROSBI ID 139323)
Prilog u časopisu | izvorni znanstveni rad | međunarodna recenzija
Podaci o odgovornosti
Eda, Katsuya ; Matijević, Vlasta
engleski
Finite index supergroups and subgroups of torsionfree abelian groups of rank two
Every torsionfree abelian group A of rank two is a subgroup of QxQ and is expressed as a direct limit of free abelian groups of rank two with lower diagonal integer-valued 2×2-matrices as the bonding maps. Using these direct systems we classify all subgroups of QxQ which are finite index supergroups of A or finite index subgroups of A. Furthermore, we prove that for each prime p there exists a torsionfree abelian group A such that each pair of distinct s-index supergroups of A are non-isomorphic and each pair of distinct s-index subgroups of A are non-isomorphic.
Torsionfree abelian group; rank two; finite index; subgroup; supergroup
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano
nije evidentirano